Buongiorno, mi pare di aver già letto di questo problema qui ma non lo trovo.
Dunque, io ho libero come pagina iniziale in win 7 (IE 9, mi pare). Mentre la navigazione sul portale non presenta problemi, da un po' di tempo quando uso la stringa di ricerca mi viene il messaggio “non è possibile elaborare la tua richiesta in quanto un virus o un’applicazione spyware ci invia richieste automatiche e il tuo computer o la tua rete potrebbero essere stati infettati. Ti consigliamo di eseguire un programma antivirus o antispyware...". Ho fatto una scansione completa con Norton e non ha rilevato niente. D'altra parte Google Chrome, che ho installato anche se lo mantengo separato, non rileva alcun problema e fa la sua ricerca. Ho anche resettato le impostazioni di IE. Di cosa si può trattare e come risolverlo? Putroppo la ricerca in Libero aiuto è lunghissima e farraginosa.
Vi posto il log
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 09:28:03, on 27/09/2012
Platform: Unknown Windows (WinNT 6.01.3505 SP1)
MSIE: Internet Explorer v9.00 (9.00.8112.16450)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskhost.exe
C:\Program Files\Norton AntiVirus\Engine\18.7.1.3\ccSvcHst.exe
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\VIA\VIAudioi\VDeck\VDeck.exe
C:\Program Files\CyberLink\Power2Go\CLMLSvc.exe
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\MOM.exe
C:\Program Files\Common Files\Java\Java Update\jusched.exe
C:\Program Files\Microsoft Office\Office14\ONENOTEM.EXE
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\CCC.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Windows\system32\Macromed\Flash\FlashUtil32_11_4_402_265_ActiveX.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe
C:\Program Files\Microsoft Office\Office14\WINWORD.EXE
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Google\Google Earth\plugin\geplugin.exe
C:\Windows\system32\taskhost.exe
C:\Program Files\Windows Live\Mail\wlmail.exe
C:\Program Files\Windows Live\Contacts\wlcomm.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Windows\system32\SearchFilterHost.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = Preserve
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.libero.it/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - URLSearchHook: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Symantec Intrusion Prevention - {6D53EC84-6AAE-4787-AEEE-F4628F01010C} - C:\Program Files\Norton AntiVirus\Engine\18.7.1.3\IPS\IPSBHO.DLL
O2 - BHO: Java(tm) Plug-In SSV Helper - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre6\bin\ssv.dll
O2 - BHO: Windows Live ID Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: URLRedirectionBHO - {B4F3A835-0E21-4959-BA22-42B3008E02FF} - C:\PROGRA~1\MICROS~1\Office14\URLREDIR.DLL
O2 - BHO: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O3 - Toolbar: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O4 - HKLM\..\Run: [HDAudDeck] C:\Program Files\VIA\VIAudioi\VDeck\VDeck.exe -r
O4 - HKLM\..\Run: [UpdateLBPShortCut] "C:\Program Files\CyberLink\LabelPrint\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\LabelPrint" UpdateWithCreateOnce "Software\CyberLink\LabelPrint\2.5"
O4 - HKLM\..\Run: [CLMLServer] "C:\Program Files\CyberLink\Power2Go\CLMLSvc.exe"
O4 - HKLM\..\Run: [UpdateP2GoShortCut] "C:\Program Files\CyberLink\Power2Go\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\Power2Go" UpdateWithCreateOnce "SOFTWARE\CyberLink\Power2Go\6.0"
O4 - HKLM\..\Run: [UpdatePSTShortCut] "C:\Program Files\CyberLink\DVD Suite\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\DVD Suite" UpdateWithCreateOnce "Software\CyberLink\PowerStarter"
O4 - HKLM\..\Run: [StartCCC] "C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe" MSRun
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe ARM] "C:\Program Files\Common Files\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Common Files\Java\Java Update\jusched.exe"
O4 - HKLM\..\Run: [SearchSettings] "C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe"
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'SERVIZIO DI RETE')
O4 - Startup: Ritaglio schermata e avvio di OneNote 2010.lnk = C:\Program Files\Microsoft Office\Office14\ONENOTEM.EXE
O9 - Extra button: Invia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\Program Files\Microsoft Office\Office14\ONBttnIE.dll
O9 - Extra 'Tools' menuitem: I&nvia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\Program Files\Microsoft Office\Office14\ONBttnIE.dll
O9 - Extra button: &Note collegate di OneNote - {789FE86F-6FC4-46A1-9849-EDE0DB0C95CA} - C:\Program Files\Microsoft Office\Office14\ONBttnIELinkedNotes.dll
O9 - Extra 'Tools' menuitem: &Note collegate di OneNote - {789FE86F-6FC4-46A1-9849-EDE0DB0C95CA} - C:\Program Files\Microsoft Office\Office14\ONBttnIELinkedNotes.dll
O10 - Unknown file in Winsock LSP: c:\program files\common files\microsoft shared\windows live\wlidnsp.dll
O10 - Unknown file in Winsock LSP: c:\program files\common files\microsoft shared\windows live\wlidnsp.dll
O11 - Options group: [ACCELERATED_GRAPHICS] Accelerated graphics
O13 - Gopher Prefix:
O16 - DPF: {02BF25D5-8C17-4B23-BC80-D3488ABDDC6B} (QuickTime Plugin Control) - http://appldnld.apple.com.edgesuite.net/content.info.apple.com/QuickTime/qtactivex/qtplugin.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O18 - Protocol: x-owacid - {0215258F-F0A8-49DE-BF1B-0FF02EDA8807} - C:\Program Files\Microsoft\Outlook Web Access SMIME Client\mimectl.dll
O18 - Filter hijack: text/xml - {807573E5-5146-11D5-A672-00B0D022E945} - C:\Program Files\Common Files\Microsoft Shared\OFFICE14\MSOXMLMF.DLL
O23 - Service: Adobe Flash Player Update Service (AdobeFlashPlayerUpdateSvc) - Adobe Systems Incorporated - C:\Windows\system32\Macromed\Flash\FlashPlayerUpdateService.exe
O23 - Service: AMD External Events Utility - AMD - C:\Windows\system32\atiesrxx.exe
O23 - Service: Application Updater - Spigot, Inc. - C:\Program Files\Application Updater\ApplicationUpdater.exe
O23 - Service: Servizio Google Update (gupdate) (gupdate) - Google Inc. - C:\Program Files\Google\Update\GoogleUpdate.exe
O23 - Service: Servizio Google Update (gupdatem) (gupdatem) - Google Inc. - C:\Program Files\Google\Update\GoogleUpdate.exe
O23 - Service: Norton AntiVirus (NAV) - Symantec Corporation - C:\Program Files\Norton AntiVirus\Engine\18.7.1.3\ccSvcHst.exe
O23 - Service: VIA Karaoke digital mixer Service (VIAKaraokeService) - VIA Technologies, Inc. - C:\Windows\system32\viakaraokesrv.exe

--
End of file - 8004 bytes

Sei infettato da spigot che è un troian, le scansioni con antivirus non servono a niente perchè se l'infezione è passata la scansione non rileva niente, anche fra gli AV più quotati e a pagamento come Norton.

Controlla fra i programmi installati se hai Spigot\Search Settings\SearchSettings.exe e se c'è rimuovilo, oppure segui questo percorso; C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe e rimuovi tutto.
Poi vai in Pannello di controllo - Strumenti amministrazione - Servizi e cerca la voce Spigot, Inc. - oppure Application Updater se c'è fai doppio clic su di essa e poi in Tipo di avvio metti Disabilitato OK esci.

Chiudi tutti i programmi e disconnesso lanci HJT e clicca sul secondo pulsante: Do a system scan only poi metti la spunta alle voci che ti indico e alla fine clic su Fix checked:

C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe
R3 - URLSearchHook: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O2 - BHO: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O3 - Toolbar: pdfforge Toolbar - {B922D405-6D13-4A2B-AE89-08A030DA4402} - C:\Program Files\pdfforge Toolbar\IE\6.3\pdfforgeToolbarIE.dll
O4 - HKLM\..\Run: [UpdateLBPShortCut] "C:\Program Files\CyberLink\LabelPrint\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\LabelPrint" UpdateWithCreateOnce "Software\CyberLink\LabelPrint\2.5"
O4 - HKLM\..\Run: [UpdateP2GoShortCut] "C:\Program Files\CyberLink\Power2Go\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\Power2Go" UpdateWithCreateOnce "SOFTWARE\CyberLink\Power2Go\6.0"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe ARM] "C:\Program Files\Common Files\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [SearchSettings] "C:\Program Files\Common Files\Spigot\Search Settings\SearchSettings.exe"
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'SERVIZIO DI RETE')
O4 - Startup: Ritaglio schermata e avvio di OneNote 2010.lnk = C:\Program Files\Microsoft Office\Office14\ONENOTEM.EXE

Poi fai una pulizia con Ccleaner compreso il Registro.

Poi Scarica Adwcleaner sul desktop:
http://general-changelog-team.fr/en/downloads/finish/20-outils-de-xplode/2-adwcleaner
Avvialo e clicca sul pulsante "Elimina".
Conferma con OK le varie finestre che ti compariranno.
Il pc si riavvierà, e uscirà il log con le eliminazioni.
Postalo qui.

A risentirci, ciao.

inoltre le righe
O4 - HKLM\..\Run: [UpdateLBPShortCut] "C:\Program Files\CyberLink\LabelPrint\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\LabelPrint" UpdateWithCreateOnce "Software\CyberLink\LabelPrint\2.5"
O4 - HKLM\..\Run: [UpdateP2GoShortCut] "C:\Program Files\CyberLink\Power2Go\MUITransfer\MUIStartMenu.exe" "C:\Program Files\CyberLink\Power2Go" UpdateWithCreateOnce "SOFTWARE\CyberLink\Power2Go\6.0"
tornano ad ogni nuova scansione di HT

Il problema c'è ancora ovvero libero mi continua a dare quel messaggio.
Ho visto cercando il nome del trojan sul web che virit lo elimina. Posso provare con quello?

riaprendo il pc dopo un certo periodo non mi è più comparso il messaggio di Libero, però ho voluto fare lo stesso la scansione con virit, che ha trovato un file infetto. Non ho capito cosa ne ha fatto. allego il log . All'inizio non avevo messo i privilegi di amministratore, per cui nella prima parte non vedeva alcuni files.
VirIT eXplorer Lite Log

[SCANSIONE DELLA MEMORIA]
[Hidden Services]
BHDrvx86 - BHDrvx86 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\BASHDefs\20130107.001\BHDrvx86.sys
eeCtrl - Symantec Eraser Control driver - \??\C:\Program Files\Common Files\Symantec Shared\EENGINE\eeCtrl.sys
IDSVix86 - IDSVix86 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\IPSDefs\20130108.002\IDSvix86.sys
SRTSPX - Symantec Real Time Storage Protection (PEL) - \SystemRoot\system32\drivers\NAV\1207010.003\SRTSPX.SYS
SymDS - Symantec Data Store - system32\drivers\NAV\1207010.003\SYMDS.SYS
SymEFA - Symantec Extended File Attributes - system32\drivers\NAV\1207010.003\SYMEFA.SYS
SymIRON - Symantec Iron Driver - \SystemRoot\system32\drivers\NAV\1207010.003\Ironx86.SYS
SymNetS - Symantec Network Security WFP Driver - \SystemRoot\System32\Drivers\NAV\1207010.003\SYMNETS.SYS
EraserUtilRebootDrv - EraserUtilRebootDrv - \??\C:\Program Files\Common Files\Symantec Shared\EENGINE\EraserUtilRebootDrv.sys
NAVENG - NAVENG - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\VirusDefs\20130108.022\NAVENG.SYS
NAVEX15 - NAVEX15 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\VirusDefs\20130108.022\NAVEX15.SYS
SRTSP - Symantec Real Time Storage Protection - \SystemRoot\System32\Drivers\NAV\1207010.003\SRTSP.SYS
SymEvent - \??\C:\Windows\system32\Drivers\SYMEVENT.SYS

OK

---

10/01/2013 - 15:49:29

[SCANSIONE DEL REGISTRO]
OK

[C:]
MASTER BOOT RECORD: Non analizzato, mancano i privilegi di amministratore
BOOT SECTOR: Non analizzato, mancano i privilegi di amministratore

C:\BCD\BINcds\wxppro\files\bin\mkisofs.exe Possibile variante da Backdoor.SdBot.DW
[SCANSIONE DELLA MEMORIA]
[Hidden Services]
BHDrvx86 - BHDrvx86 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\BASHDefs\20130107.001\BHDrvx86.sys
eeCtrl - Symantec Eraser Control driver - \??\C:\Program Files\Common Files\Symantec Shared\EENGINE\eeCtrl.sys
IDSVix86 - IDSVix86 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\IPSDefs\20130108.002\IDSvix86.sys
SRTSPX - Symantec Real Time Storage Protection (PEL) - \SystemRoot\system32\drivers\NAV\1207010.003\SRTSPX.SYS
SymDS - Symantec Data Store - system32\drivers\NAV\1207010.003\SYMDS.SYS
SymEFA - Symantec Extended File Attributes - system32\drivers\NAV\1207010.003\SYMEFA.SYS
SymIRON - Symantec Iron Driver - \SystemRoot\system32\drivers\NAV\1207010.003\Ironx86.SYS
SymNetS - Symantec Network Security WFP Driver - \SystemRoot\System32\Drivers\NAV\1207010.003\SYMNETS.SYS
EraserUtilRebootDrv - EraserUtilRebootDrv - \??\C:\Program Files\Common Files\Symantec Shared\EENGINE\EraserUtilRebootDrv.sys
NAVENG - NAVENG - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\VirusDefs\20130108.022\NAVENG.SYS
NAVEX15 - NAVEX15 - \??\C:\ProgramData\Norton\{0C55C096-0F1D-4F28-AAA2-85EF591126E7}\NAV_18.5.0.125\Definitions\VirusDefs\20130108.022\NAVEX15.SYS
SRTSP - Symantec Real Time Storage Protection - \SystemRoot\System32\Drivers\NAV\1207010.003\SRTSP.SYS
SymEvent - \??\C:\Windows\system32\Drivers\SYMEVENT.SYS

OK

---

10/01/2013 - 15:51:07

[SCANSIONE DEL REGISTRO]
OK

[C:]
MASTER BOOT RECORD (\\.\PhysicalDrive0): OK
BOOT SECTOR: OK

C:\BCD\BINcds\wxppro\files\bin\mkisofs.exe Possibile variante da Backdoor.SdBot.DW

[D:]


[E:]
BOOT SECTOR: OK


Chiavi Registro infette: 0.
Files Infetti: 1.
Files Sospetti: 0.
Files Analizzati: 140872.
Files Totali: 140872.
Chiavi Registro rimosse: 0.
Virus Rimossi: 0.

Va bene così o devo fare qualcos'altro?