Office è normale. Non ho scaricato nulla ultimamente.


Ecco il log completo:

Logfile of Trend Micro HijackThis v2.0.5
Scan saved at 09:51:29, on 21/11/2015
Platform: Windows 7 SP1 (WinNT 6.00.3505)
MSIE: Internet Explorer v11.0 (11.00.9600.18098)

FIREFOX: 42.0 (x86 it)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Avira\AntiVir Desktop\avgnt.exe
C:\Windows\System32\igfxtray.exe
C:\Windows\System32\hkcmd.exe
C:\Program Files\Malwarebytes Anti-Malware\mbam.exe
C:\Windows\system32\DllHost.exe
C:\Program Files\Avira\Launcher\Avira.Systray.exe
C:\Windows\system32\taskmgr.exe
C:\Users\Mario\Desktop\HijackThis.exe
C:\Windows\system32\SearchFilterHost.exe
C:\Windows\system32\DllHost.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = about:blank
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 = about:blank
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = about:blank
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = about:blank
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
O2 - BHO: Java(tm) Plug-In SSV Helper - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.8.0_60\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: SkypeIEPluginBHO - {AE805869-2E5C-4ED4-8F7B-F1F7851A4497} - C:\Program Files\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
O2 - BHO: URLRedirectionBHO - {B4F3A835-0E21-4959-BA22-42B3008E02FF} - C:\PROGRA~1\MICROS~2\Office14\URLREDIR.DLL
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre1.8.0_60\bin\jp2ssv.dll
O3 - Toolbar: Easy Photo Print - {9421DD08-935F-4701-A9CA-22DF90AC4EA6} - C:\Program Files\Epson Software\Easy Photo Print\EPTBL.dll
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\Avira\AntiVir Desktop\avgnt.exe" /min
O4 - HKLM\..\Run: [IgfxTray] C:\Windows\system32\igfxtray.exe
O4 - HKLM\..\Run: [HotKeysCmds] C:\Windows\system32\hkcmd.exe
O4 - HKLM\..\Run: [Avira SystrayStartTrigger] C:\Program Files\Avira\Launcher\Avira.SystrayStartTrigger.exe
O4 - HKLM\..\Run: [Speedup_umh] C:\Program Files\Avira\AviraSpeedup\Speedup_umh.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')
O9 - Extra button: @C:\Program Files\Windows Live\Writer\WindowsLiveWriterShortcuts.dll,-1004 - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
O9 - Extra 'Tools' menuitem: @C:\Program Files\Windows Live\Writer\WindowsLiveWriterShortcuts.dll,-1003 - {219C3416-8CB2-491a-A3C7-D9FCDDC9D600} - C:\Program Files\Windows Live\Writer\WriterBrowserExtension.dll
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
O9 - Extra button: Skype Click to Call settings - {898EA8C8-E7FF-479B-8935-AEC46303B9E5} - C:\Program Files\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.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
O17 - HKLM\System\CCS\Services\Tcpip\..\{50E29751-08E8-4410-A8DF-CDCCA6CF88B2}: NameServer = 8.8.8.8,8.8.4.4
O18 - Protocol: skype4com - (no CLSID) - (no file)
O18 - Protocol: skypec2c - {91774881-D725-4E58-B298-07617B9B86A8} - C:\Program Files\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
O18 - Protocol: wlpg - {E43EF6CD-A37A-4A9B-9E6F-83F89B8E6324} - C:\Program Files\Windows Live\Photo Gallery\AlbumDownloadProtocolHandler.dll
O18 - Filter hijack: text/xml - {807573E5-5146-11D5-A672-00B0D022E945} - C:\Program Files\Common Files\Microsoft Shared\OFFICE14\MSOXMLMF.DLL
O23 - Service: Adobe Acrobat Update Service (AdobeARMservice) - Adobe Systems Incorporated - C:\Program Files\Common Files\Adobe\ARM\1.0\armsvc.exe
O23 - Service: Adobe Flash Player Update Service (AdobeFlashPlayerUpdateSvc) - Adobe Systems Incorporated - C:\Windows\system32\Macromed\Flash\FlashPlayerUpdateService.exe
O23 - Service: Avira Mail Protection (AntiVirMailService) - Avira Operations GmbH & Co. KG - C:\Program Files\Avira\AntiVir Desktop\avmailc7.exe
O23 - Service: Avira Pianificatore (AntiVirSchedulerService) - Avira Operations GmbH & Co. KG - C:\Program Files\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira Real-Time Protection (AntiVirService) - Avira Operations GmbH & Co. KG - C:\Program Files\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Avira Web Protection (AntiVirWebService) - Avira Operations GmbH & Co. KG - C:\Program Files\Avira\AntiVir Desktop\avwebg7.exe
O23 - Service: Avira Service Host (Avira.ServiceHost) - Avira Operations GmbH & Co. KG - C:\Program Files\Avira\Launcher\Avira.ServiceHost.exe
O23 - Service: FsUsbExService - Teruten - C:\Windows\system32\FsUsbExService.Exe
O23 - Service: Servizio di 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: MBAMScheduler - Malwarebytes - C:\Program Files\Malwarebytes Anti-Malware\mbamscheduler.exe
O23 - Service: MBAMService - Malwarebytes - C:\Program Files\Malwarebytes Anti-Malware\mbamservice.exe
O23 - Service: Skype Updater (SkypeUpdate) - Skype Technologies - C:\Program Files\Skype\Updater\Updater.exe
O23 - Service: SAMSUNG Mobile Connectivity Service (ss_conn_service) - DEVGURU Co., LTD. - C:\Program Files\Samsung\USB Drivers\25_escape\conn\ss_conn_service.exe

--
End of file - 7026 bytes

dopo ctrl + alt + canc non esiste la voce avvio...

Grazi mille!
Avevo già provato con un avvio pulito ma senza benefici. Il PC mi sembra troppo instabile e credo che c'è qualcosa che mi sfugge forse nella corruzione del profilo e dei relativi permessi di amministrazione. Inoltre sto vedendo oggi che la connessione WIFI chiede continuamente l'autenticazione che poi si ristabilisce da sola...boh!?
Ottimo il suggerimento del dissipatore ed ora mi appresto a smontare e pulire.
Grazie ancora del prezioso aiuto

Sì è protetta WPA2-Personal.
Il mio PC ha strane nevrosi.
Comunque dopo la pulizia le prestazioni sono un po' migliorate quindi ti ringrazio ancora per l'aiuto