Da qualche giorno non mi funziona più Firefox, si chiude poco dopo la sua apertura oppure mi apre una pagina di pubblicità non richiesta.
Ho fatto la scansione di tutto il sistema con l'antivirus (Norton) ma, non mi ha trovato niente.

La scansione con HijackThis ed il logfile è:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 15.59.27, on 13/06/2011
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Programmi\File comuni\Apple\Mobile Device Support\AppleMobileDeviceService.exe
C:\Programmi\Bonjour\mDNSResponder.exe
C:\Programmi\Java\jre6\bin\jqs.exe
C:\Programmi\Nero\Nero8\Nero BackItUp\NBService.exe
C:\Programmi\Norton Internet Security\Engine\17.8.0.5\ccSvcHst.exe
C:\WINDOWS\RTHDCPL.EXE
C:\WINDOWS\system32\VTTimer.exe
C:\WINDOWS\system32\S3trayp.exe
C:\Programmi\Google\Google Desktop Search\GoogleDesktop.exe
C:\Programmi\Google\Google Desktop Search\GoogleDesktop.exe
C:\WINDOWS\system32\PSIService.exe
C:\Programmi\iTunes\iTunesHelper.exe
C:\WINDOWS\system32\svchost.exe
C:\Programmi\File comuni\Java\Java Update\jusched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\Messenger\msmsgs.exe
C:\Programmi\Logitech\Desktop Messenger\8876480\Program\LogitechDesktopMessenger.exe
C:\Programmi\Canon\CAL\CALMAIN.exe
C:\Programmi\Spamihilator\spamihilator.exe
C:\Programmi\Norton Internet Security\Engine\17.8.0.5\ccSvcHst.exe
C:\Programmi\iPod\bin\iPodService.exe
C:\WINDOWS\system32\wbem\wmiapsrv.exe
C:\Programmi\internet explorer\iexplore.exe
C:\Programmi\internet explorer\iexplore.exe
C:\Programmi\internet explorer\iexplore.exe
C:\Programmi\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = about:blank
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 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page =
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Programmi\File comuni\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Symantec NCO BHO - {602ADB0E-4AFF-4217-8AA1-95DAC4DFA408} - C:\Programmi\Norton Internet Security\Engine\17.8.0.5\coIEPlg.dll
O2 - BHO: Symantec Intrusion Prevention - {6D53EC84-6AAE-4787-AEEE-F4628F01010C} - C:\Programmi\Norton Internet Security\Engine\17.8.0.5\IPSBHO.DLL
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Programmi\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Programmi\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O2 - BHO: EpsonToolBandKicker Class - {E99421FB-68DD-40F0-B4AC-B7027CAE2F1A} - C:\Programmi\EPSON\EPSON Web-To-Page\EPSON Web-To-Page.dll
O3 - Toolbar: EPSON Web-To-Page - {EE5D279F-081B-4404-994D-C6B60AAEBA6D} - C:\Programmi\EPSON\EPSON Web-To-Page\EPSON Web-To-Page.dll
O3 - Toolbar: Norton Toolbar - {7FEBEFE3-6B19-4349-98D2-FFB09D4B49CA} - C:\Programmi\Norton Internet Security\Engine\17.8.0.5\coIEPlg.dll
O4 - HKLM\..\Run: [RTHDCPL] RTHDCPL.EXE
O4 - HKLM\..\Run: [VTTimer] VTTimer.exe
O4 - HKLM\..\Run: [S3Trayp] S3trayp.exe
O4 - HKLM\..\Run: [Kernel and Hardware Abstraction Layer] KHALMNPR.EXE
O4 - HKLM\..\Run: [Google Desktop Search] "C:\Programmi\Google\Google Desktop Search\GoogleDesktop.exe" /startup
O4 - HKLM\..\Run: [QuickTime Task] "C:\Programmi\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "C:\Programmi\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Programmi\Adobe\Reader 10.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe ARM] "C:\Programmi\File comuni\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Programmi\File comuni\Java\Java Update\jusched.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Programmi\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [LDM] C:\Programmi\Logitech\Desktop Messenger\8876480\Program\LogitechDesktopMessenger.exe
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'Default user')
O4 - S-1-5-18 Startup: Spamihilator.lnk = C:\Programmi\Spamihilator\spamihilator.exe (User 'SYSTEM')
O4 - .DEFAULT Startup: Spamihilator.lnk = C:\Programmi\Spamihilator\spamihilator.exe (User 'Default user')
O4 - Startup: Spamihilator.lnk = C:\Programmi\Spamihilator\spamihilator.exe
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Ricerche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Programmi\Messenger\msmsgs.exe
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://www.update.microsoft.com/windowsupdate/v6/V5Controls/en/x86/client/wuweb_site.cab?1203603426140
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O20 - AppInit_DLLs: C:\PROGRA~1\Google\GOOGLE~1\GOEC62~1.DLL
O23 - Service: Adobe LM Service - Adobe Systems - C:\Programmi\File comuni\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Programmi\File comuni\Apple\Mobile Device Support\AppleMobileDeviceService.exe
O23 - Service: Servizio Bonjour (Bonjour Service) - Apple Inc. - C:\Programmi\Bonjour\mDNSResponder.exe
O23 - Service: Canon Camera Access Library 8 (CCALib8) - Canon Inc. - C:\Programmi\Canon\CAL\CALMAIN.exe
O23 - Service: Google Desktop Manager 5.9.1005.12335 (GoogleDesktopManager-051210-111108) - Google - C:\Programmi\Google\Google Desktop Search\GoogleDesktop.exe
O23 - Service: Servizio iPod (iPod Service) - Apple Inc. - C:\Programmi\iPod\bin\iPodService.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Programmi\Java\jre6\bin\jqs.exe
O23 - Service: Logitech Bluetooth Service (LBTServ) - Logitech, Inc. - C:\Programmi\File comuni\Logitech\Bluetooth\LBTServ.exe
O23 - Service: Nero BackItUp Scheduler 3 - Nero AG - C:\Programmi\Nero\Nero8\Nero BackItUp\NBService.exe
O23 - Service: Norton Internet Security (NIS) - Symantec Corporation - C:\Programmi\Norton Internet Security\Engine\17.8.0.5\ccSvcHst.exe
O23 - Service: NMIndexingService - Nero AG - C:\Programmi\File comuni\Nero\Lib\NMIndexingService.exe
O23 - Service: ProtexisLicensing - Unknown owner - C:\WINDOWS\system32\PSIService.exe

--
End of file - 7392 bytes

Chiedo se qualcuno può aiutarmi a risolavere il problema.
Grazie

Il log non è chiaro, scarica l'ultima vs di HJT la 2.0.4, la trovi su aiutamici e poi rifai la scansione e posta il nuovo log.

Tutto a posto il log è pulito, prova a rimuovere firefox e poi reinstallalo scaricando la nuova versione dal sito
QUI. poi installa il componente aggiuntivo Adblock Plus che blocca
la pubblicità dei siti, QUI clic sulla prima voce e poi Aggiungi a Firefox.