Credo di aver preso un virus. In i.e. la prima pagina è cambiata :mystartsearch.com
Vi mando il log, per cortesia me lo potete controllare? Grazie mille.
Logfile of Trend Micro HijackThis v2.0.5
Scan saved at 20:28:12, on 27/01/2015
Platform: Unknown Windows (WinNT 6.02.1008)
MSIE: Internet Explorer v11.0 (11.00.9600.17416)

FIREFOX: 35.0.1 (x86 it)
Boot mode: Normal

Running processes:
C:\Program Files (x86)\NVIDIA Corporation\Update Core\NvBackend.exe
C:\Program Files (x86)\Hewlett-Packard\HP CoolSense\CoolSense.exe
C:\Program Files (x86)\CyberLink\YouCam\YouCamService.exe
C:\Program Files (x86)\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
C:\Program Files\Intel\Intel(R) Smart Connect Technology Agent\iSCTsysTray8.exe
C:\Program Files (x86)\Hewlett-Packard\HP System Event\HPMSGSVC.exe
C:\Program Files\AVAST Software\Avast\avastui.exe
C:\Program Files (x86)\Spybot - Search & Destroy 2\SDTray.exe
C:\Program Files (x86)\HP\HP Software Update\hpwuschd2.exe
C:\Users\rosa\Downloads\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
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = www.google.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = www.google.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = www.google.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = www.google.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,First Home Page = http://g.uk.msn.com/HPCON14/6
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = C:\Windows\SysWOW64\blank.htm
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
F2 - REG:system.ini: UserInit=userinit.exe,
O3 - Toolbar: Google Toolbar - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - C:\Program Files (x86)\Google\Google Toolbar\GoogleToolbar_32.dll
O4 - HKLM\..\Run: [AccelerometerSysTrayApplet] C:\Program Files (x86)\Hewlett-Packard\HP 3D DriveGuard\AccelerometerST.exe
O4 - HKLM\..\Run: [HPMessageService] C:\Program Files (x86)\Hewlett-Packard\HP System Event\HPMSGSVC.exe
O4 - HKLM\..\Run: [AvastUI.exe] "C:\Program Files\AVAST Software\Avast\AvastUI.exe" /nogui
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files (x86)\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [SDTray] "C:\Program Files (x86)\Spybot - Search & Destroy 2\SDTray.exe"
O4 - HKLM\..\Run: [HP Software Update] C:\Program Files (x86)\Hp\HP Software Update\HPWuSchd2.exe
O4 - HKCU\..\Run: [CCleaner Monitoring] "C:\Program Files\CCleaner\CCleaner64.exe" /MONITOR
O4 - HKCU\..\Run: [EADM] "C:\Program Files (x86)\Origin\Origin.exe" -AutoStart
O4 - HKCU\..\Run: [Spybot-S&D Cleaning] "C:\Program Files (x86)\Spybot - Search & Destroy 2\SDCleaner.exe" /autoclean
O4 - HKCU\..\Run: [swg] "C:\Program Files (x86)\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe"
O4 - Global Startup: ISCTSystray.lnk = C:\Program Files\Intel\Intel(R) Smart Connect Technology Agent\iSCTsysTray8.exe
O9 - Extra button: HP Smart Print - {22CC3EBD-C286-43aa-B8E6-06B115F74162} - C:\Program Files (x86)\Hewlett-Packard\Smart Print\SmartPrintSetup.exe
O9 - Extra 'Tools' menuitem: HP Smart Print - {22CC3EBD-C286-43aa-B8E6-06B115F74162} - C:\Program Files (x86)\Hewlett-Packard\Smart Print\SmartPrintSetup.exe
O9 - Extra button: @C:\Program Files (x86)\Hewlett-Packard\HP Support Framework\Resources\HPNetworkCheck\HPNetworkCheckPlugin.dll,-103 - {25510184-5A38-4A99-B273-DCA8EEF6CD08} - C:\Program Files (x86)\Hewlett-Packard\HP Support Framework\Resources\HPNetworkCheck\NCLauncherFromIE.exe
O9 - Extra 'Tools' menuitem: @C:\Program Files (x86)\Hewlett-Packard\HP Support Framework\Resources\HPNetworkCheck\HPNetworkCheckPlugin.dll,-102 - {25510184-5A38-4A99-B273-DCA8EEF6CD08} - C:\Program Files (x86)\Hewlett-Packard\HP Support Framework\Resources\HPNetworkCheck\NCLauncherFromIE.exe
O9 - Extra button: Envoyer à OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~2\MICROS~1\Office12\ONBttnIE.dll
O9 - Extra 'Tools' menuitem: &Envoyer à OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~2\MICROS~1\Office12\ONBttnIE.dll
O9 - Extra button: Skype Click to Call settings - {898EA8C8-E7FF-479B-8935-AEC46303B9E5} - C:\Program Files (x86)\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~2\MICROS~1\Office12\REFIEBAR.DLL
O9 - Extra button: @C:\Program Files (x86)\Evernote\Evernote\Resource.dll,-101 - {A95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\Program Files (x86)\Evernote\Evernote\\EvernoteIERes\AddNote.html
O9 - Extra 'Tools' menuitem: @C:\Program Files (x86)\Evernote\Evernote\Resource.dll,-101 - {A95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\Program Files (x86)\Evernote\Evernote\\EvernoteIERes\AddNote.html
O11 - Options group: [ACCELERATED_GRAPHICS] Accelerated graphics
O18 - Protocol: skypec2c - {91774881-D725-4E58-B298-07617B9B86A8} - C:\Program Files (x86)\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
O20 - Winlogon Notify: SDWinLogon - SDWinLogon.dll (file missing)
O23 - Service: Adobe Flash Player Update Service (AdobeFlashPlayerUpdateSvc) - Adobe Systems Incorporated - C:\Windows\SysWOW64\Macromed\Flash\FlashPlayerUpdateService.exe
O23 - Service: @%SystemRoot%\system32\Alg.exe,-112 (ALG) - Unknown owner - C:\Windows\System32\alg.exe (file missing)
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files (x86)\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe
O23 - Service: avast! Antivirus - AVAST Software - C:\Program Files\AVAST Software\Avast\AvastSvc.exe
O23 - Service: @oem26.inf,%BlueBcmBtRSupport.SVCNAME%;Bluetooth Driver Management Service (BcmBtRSupport) - Unknown owner - C:\Windows\system32\BtwRSupportService.exe (file missing)
O23 - Service: Servizio Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Intel(R) Content Protection HECI Service (cphs) - Intel Corporation - C:\Windows\SysWow64\IntelCpHeciSvc.exe
O23 - Service: @%SystemRoot%\system32\efssvc.dll,-100 (EFS) - Unknown owner - C:\Windows\System32\lsass.exe (file missing)
O23 - Service: @%systemroot%\system32\fxsresm.dll,-118 (Fax) - Unknown owner - C:\Windows\system32\fxssvc.exe (file missing)
O23 - Service: GamesAppIntegrationService - WildTangent - C:\Program Files (x86)\WildTangent Games\App\GamesAppIntegrationService.exe
O23 - Service: GamesAppService - WildTangent, Inc. - C:\Program Files (x86)\WildTangent Games\App\GamesAppService.exe
O23 - Service: NVIDIA GeForce Experience Service (GfExperienceService) - NVIDIA Corporation - C:\Program Files\NVIDIA Corporation\GeForce Experience Service\GfExperienceService.exe
O23 - Service: Servizio Google Update (gupdate) (gupdate) - Google Inc. - C:\Program Files (x86)\Google\Update\GoogleUpdate.exe
O23 - Service: Servizio Google Update (gupdatem) (gupdatem) - Google Inc. - C:\Program Files (x86)\Google\Update\GoogleUpdate.exe
O23 - Service: Google Software Updater (gusvc) - Google - C:\Program Files (x86)\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: HP Support Assistant Service - Hewlett-Packard Company - C:\Program Files (x86)\Hewlett-Packard\HP Support Framework\hpsa_service.exe
O23 - Service: HP Software Framework Service (hpqwmiex) - Hewlett-Packard Company - C:\Program Files (x86)\Hewlett-Packard\Shared\hpqwmiex.exe
O23 - Service: @oem25.inf,%hpservice_desc%;HP Service (hpsrv) - Unknown owner - C:\Windows\system32\Hpservice.exe (file missing)
O23 - Service: HPWMISVC - Hewlett-Packard Development Company, L.P. - C:\Program Files (x86)\Hewlett-Packard\HP System Event\HPWMISVC.exe
O23 - Service: Intel(R) Rapid Storage Technology (IAStorDataMgrSvc) - Intel Corporation - C:\Program Files\Intel\Intel(R) Rapid Storage Technology\IAStorDataMgrSvc.exe
O23 - Service: @%SystemRoot%\system32\ieetwcollectorres.dll,-1000 (IEEtwCollectorService) - Unknown owner - C:\Windows\system32\IEEtwCollector.exe (file missing)
O23 - Service: Intel(R) HD Graphics Control Panel Service (igfxCUIService1.0.0.0) - Unknown owner - C:\Windows\system32\igfxCUIService.exe (file missing)
O23 - Service: Intel(R) Capability Licensing Service Interface - Intel(R) Corporation - C:\Program Files\Intel\iCLS Client\HeciServer.exe
O23 - Service: Intel(R) Capability Licensing Service TCP IP Interface - Intel(R) Corporation - C:\Program Files\Intel\iCLS Client\SocketHeciServer.exe
O23 - Service: Intel(R) ME Service - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\FWService\IntelMeFWService.exe
O23 - Service: Servizio iPod (iPod Service) - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: Intel(R) Smart Connect Technology Agent (ISCTAgent) - Unknown owner - C:\Program Files\Intel\Intel(R) Smart Connect Technology Agent\iSCTAgent.exe
O23 - Service: Intel(R) Dynamic Application Loader Host Interface Service (jhi_service) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL\jhi_service.exe
O23 - Service: @keyiso.dll,-100 (KeyIso) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: Intel(R) Management and Security Application Local Management Service (LMS) - Intel Corporation - C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\LMS\LMS.exe
O23 - Service: Mozilla Maintenance Service (MozillaMaintenance) - Mozilla Foundation - C:\Program Files (x86)\Mozilla Maintenance Service\maintenanceservice.exe
O23 - Service: @comres.dll,-2797 (MSDTC) - Unknown owner - C:\Windows\System32\msdtc.exe (file missing)
O23 - Service: @%SystemRoot%\System32\netlogon.dll,-102 (Netlogon) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: NVIDIA Network Service (NvNetworkService) - NVIDIA Corporation - C:\Program Files (x86)\NVIDIA Corporation\NetService\NvNetworkService.exe
O23 - Service: NVIDIA Streamer Service (NvStreamSvc) - NVIDIA Corporation - C:\Program Files\NVIDIA Corporation\NvStreamSrv\nvstreamsvc.exe
O23 - Service: NVIDIA Display Driver Service (nvsvc) - Unknown owner - C:\Windows\system32\nvvsvc.exe (file missing)
O23 - Service: HP SimplePass Service (omniserv) - Softex Inc. - C:\Program Files\Hewlett-Packard\SimplePass\OmniServ.exe
O23 - Service: Origin Client Service - Electronic Arts - C:\Program Files (x86)\Origin\OriginClientService.exe
O23 - Service: Cyberlink RichVideo64 Service(CRVS) (RichVideo64) - Unknown owner - C:\Program Files\CyberLink\Shared files\RichVideo64.exe
O23 - Service: @%systemroot%\system32\Locator.exe,-2 (RpcLocator) - Unknown owner - C:\Windows\system32\locator.exe (file missing)
O23 - Service: Realtek Audio Service (RtkAudioService) - Realtek Semiconductor - C:\Program Files\Realtek\Audio\HDA\RtkAudioService64.exe
O23 - Service: @%SystemRoot%\system32\samsrv.dll,-1 (SamSs) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: Spybot-S&D 2 Scanner Service (SDScannerService) - Safer-Networking Ltd. - C:\Program Files (x86)\Spybot - Search & Destroy 2\SDFSSvc.exe
O23 - Service: Spybot-S&D 2 Updating Service (SDUpdateService) - Safer-Networking Ltd. - C:\Program Files (x86)\Spybot - Search & Destroy 2\SDUpdSvc.exe
O23 - Service: Spybot-S&D 2 Security Center Service (SDWSCService) - Safer-Networking Ltd. - C:\Program Files (x86)\Spybot - Search & Destroy 2\SDWSCSvc.exe
O23 - Service: Skype Updater (SkypeUpdate) - Skype Technologies - C:\Program Files (x86)\Skype\Updater\Updater.exe
O23 - Service: @%SystemRoot%\system32\snmptrap.exe,-3 (SNMPTRAP) - Unknown owner - C:\Windows\System32\snmptrap.exe (file missing)
O23 - Service: @%systemroot%\system32\spoolsv.exe,-1 (Spooler) - Unknown owner - C:\Windows\System32\spoolsv.exe (file missing)
O23 - Service: @%SystemRoot%\system32\sppsvc.exe,-101 (sppsvc) - Unknown owner - C:\Windows\system32\sppsvc.exe (file missing)
O23 - Service: SynTPEnh Caller Service (SynTPEnhService) - Synaptics Incorporated - C:\Program Files\Synaptics\SynTP\SynTPEnhService.exe
O23 - Service: @%SystemRoot%\system32\ui0detect.exe,-101 (UI0Detect) - Unknown owner - C:\Windows\system32\UI0Detect.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vaultsvc.dll,-1003 (VaultSvc) - Unknown owner - C:\Windows\system32\lsass.exe (file missing)
O23 - Service: @%SystemRoot%\system32\vds.exe,-100 (vds) - Unknown owner - C:\Windows\System32\vds.exe (file missing)
O23 - Service: @%systemroot%\system32\vssvc.exe,-102 (VSS) - Unknown owner - C:\Windows\system32\vssvc.exe (file missing)
O23 - Service: @%systemroot%\system32\wbengine.exe,-104 (wbengine) - Unknown owner - C:\Windows\system32\wbengine.exe (file missing)
O23 - Service: @%ProgramFiles%\Windows Defender\MpAsDesc.dll,-320 (WdNisSvc) - Unknown owner - C:\Program Files (x86)\Windows Defender\NisSrv.exe (file missing)
O23 - Service: @%ProgramFiles%\Windows Defender\MpAsDesc.dll,-310 (WinDefend) - Unknown owner - C:\Program Files (x86)\Windows Defender\MsMpEng.exe (file missing)
O23 - Service: @%Systemroot%\system32\wbem\wmiapsrv.exe,-110 (wmiApSrv) - Unknown owner - C:\Windows\system32\wbem\WmiApSrv.exe (file missing)
O23 - Service: @%PROGRAMFILES%\Windows Media Player\wmpnetwk.exe,-101 (WMPNetworkSvc) - Unknown owner - C:\Program Files (x86)\Windows Media Player\wmpnetwk.exe (file missing)

--
End of file - 13536 bytes

mystartsearch.com è il solito browser hijacker dirottatore. Controlla nei programmi installati se trovi il sw.

Per toglierlo da I.E. fai così:

Premi e tieni premuto Alt+X.
Clicca su Gestione Componenti Aggiuntivi.
Clicca su Barre degli Strumenti ed Estensioni e disabilita l’infezione.
Clicca su Provider di Ricerca e rimuovi il nome dell’infezione dalla lista dei provider di ricerca.
Premi e tieni premuto Alt+X di nuovo e clicca su Opzioni Internet.
Sotto alla linguetta Generale, rimuovi la pagina web dell’infezione dalla sezione Pagina Iniziale.
Digita la tua pagina che preferisci e clicca OK per salvare le modifiche.

Il log non presenta problemi.

Per una pulizia approfondita fai le seguenti scansioni:

Scarica ed installa MalwareBytes: scarica la versione Gratuita non la Premium
clicca qui per il download: http://it.malwarebytes.org/
Alla fine dell'installazione nell’ultima schermata deseleziona la voce Attiva la prova gratuita di Malwarebytes Anti-Malware Pro.
Se il sw è in inglese, vai nella scheda Settings e seleziona la voce Italian dal menu a tendina Language per tradurre il programma in italiano.
Prima di fare la scansione AGGIORNALO. (è molto importante)
Poi clic su SCANSIONE seleziona la voce scansione di minaccia
Elimina gli eventuali file infetti trovati. (li devi selezionare, e poi cliccare su "Rimuovi selezionati")
Posta il log.

Scarica Adwcleaner sul desktop:
http://general-changelog-team.fr/fr/downloads/finish/20-outils-de-xplode/2-adwcleaner
Chiudi tutti i browser (è importante IE,Firefox Chrome ecc...)
Clicca sul pulsante "Scan".
Finita la scansione clicca su "Clean"
Conferma con OK le varie finestre che ti compariranno.
Il pc si riavvierà, e uscirà il log con le eliminazioni.
Postalo qui.

Scarica Junkware Removal Tool sul desktop.
http://www.majorgeeks.com/mg/get/junkware_removal_tool,1.html
Disattiva temporaneamente l'antivirus per evitare potenziali conflitti.
Doppio click su JRT
Lo strumento si aprirà e avvierà la scansione del sistema.
Devi avere pazienza in quanto questo tool può richiedere del tempo per completare la scansione .
Al termine, un log (JRT.txt) viene salvato sul desktop e si aprirà automaticamente.
Postalo qui.

Alla fine fai una pulizia con Ccleaner compreso il Registro, per il Registro acconsenti al backup quando richiesto.
Ciao