Per favore, vorrei un parere sul log che segue.
Il problema è che spesso, si blocca (apparentemente senza motivo) Windows 7.
Segnalo che dentro windows, ho installato anche UBUNTU (anch'esso si blocca più o meno con la stessa frequenza).
L'unica cosa che ho notato, è la temperatura dell'Hard Disk di Windows 7, che raggiunge 53/54 gradi.
Ringrazio anticipatamente e saluto.

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Logfile of Trend Micro HijackThis v2.0.4
Scan saved at 19:45:30, on 17/10/2010
Platform: Windows 7 (WinNT 6.00.3504)
MSIE: Internet Explorer v8.00 (8.00.7600.16671)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskhost.exe
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Avira\AntiVir Desktop\avgnt.exe
C:\Program Files\Microsoft Office\Office12\GrooveMonitor.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\Mozilla Firefox\plugin-container.exe
C:\Programmi\totalcmd\TOTALCMD.EXE
C:\Windows\system32\SearchFilterHost.exe
C:\Program Files\Trend Micro\HiJackThis\HiJackThis.exe

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.google.it/ig
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 =
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: Groove GFS Browser Helper - {72853161-30C5-4D22-B7F9-0BBC1D38A37E} - C:\PROGRA~1\MICROS~2\Office12\GR469A~1.DLL
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\5.6.5612.1312\swg.dll
O3 - Toolbar: Google Toolbar - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\Avira\AntiVir Desktop\avgnt.exe" /nosplash
O4 - HKLM\..\Run: [GrooveMonitor] "C:\Program Files\Microsoft Office\Office12\GrooveMonitor.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')
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O8 - Extra context menu item: Google Sidewiki... - res://C:\Program Files\Google\Google Toolbar\Component\GoogleToolbarDynamic_mui_en_89D8574934B26AC4.dll/cmsidewiki.html
O9 - Extra button: Invia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra 'Tools' menuitem: I&nvia a OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O17 - HKLM\System\CCS\Services\Tcpip\..\{DBBF80DE-7242-4FC8-9178-E9A88007C3F9}: NameServer = 85.37.17.5 85.38.28.77
O18 - Protocol: grooveLocalGWS - {88FED34C-F0CA-4636-A375-3CB6248B04CD} - C:\PROGRA~1\MICROS~2\Office12\GRA32A~1.DLL
O23 - Service: Avira AntiVir Scheduler (AntiVirScheduler) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\sched.exe
O23 - Service: Avira AntiVir Guard (AntiVirService) - Avira GmbH - C:\Program Files\Avira\AntiVir Desktop\avguard.exe
O23 - Service: Servizio di Google Update (gupdate) (gupdate) - Google Inc. - C:\Program Files\Google\Update\GoogleUpdate.exe
O23 - Service: Google Software Updater (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: McAfee Security Scan Component Host Service (McComponentHostService) - McAfee, Inc. - C:\Program Files\McAfee Security Scan\2.0.181\McCHSvc.exe
O23 - Service: NMSAccess - Unknown owner - C:\Program Files\CDBurnerXP\NMSAccessU.exe

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End of file - 4503 bytes

Ciao.
Elimina questo rimasuglio di McAfee , con HijackThis :

O23 - Service: McAfee Security Scan Component Host Service (McComponentHostService) - McAfee, Inc. - C:\Program Files\McAfee Security Scan\2.0.181\McCHSvc.exe

Poi segui il percorso ed elimina le cartelle in rosso:
C:\Program Files\McAfee Security Scan\2.0.181\McCHSvc.exe

Se la voce O23 non si elimina, prova in Modalità provvisoria.