Pc devenu très lent

Bonjour,
Quand j'ai allumé mon pc aujourd'hui,il était anormalement très lent, et au bout de 10 minutes environ,il se plantait,dans le gestionnaire de tache,l' UC utilisé est de 50% sans que j'ouvre quoique ce soit,et monte jusqu'à 100% si j'essaie de lancer un programme.

j'espère que je trouverais de l'aide auprès de votre forum.
Merci d'avance! et voilà un rapport hijackthis:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 17:04:34, on 07/10/2009
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Unable to get Internet Explorer version!
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:\Program Files\COMODO\COMODO Internet Security\cmdagent.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\DRIVERS\CDANTSRV.EXE
C:\Program Files\Java\jre6\bin\jqs.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\System32\TUProgSt.exe
C:\WINDOWS\system32\wuauclt.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\wbem\wmiapsrv.exe
C:\Program Files\COMODO\COMODO Internet Security\cfp.exe
C:\Program Files\Windows Live\Messenger\msnmsgr.exe
C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Documents and Settings\khalikine\Local Settings\Application Data\Google\Chrome\Application\chrome.exe
C:\Documents and Settings\khalikine\Local Settings\Application Data\Google\Chrome\Application\chrome.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.files-ftp.com/~unicorni/phpBB2/index.php
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Menara
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyServer = http=
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Fichiers communs\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: RealPlayer Download and Record Plugin for Internet Explorer - {3049C3E9-B461-4BC5-8870-4C09146192CA} - C:\Program Files\Real\RealPlayer\rpbrowserrecordplugin.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre6\bin\ssv.dll
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - C:\Program Files\Google\Google Toolbar\GoogleToolbar.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\5.2.4204.1700\swg.dll
O2 - BHO: Google Dictionary Compression sdch - {C84D72FE-E17D-4195-BB24-76C02E2E7C4E} - C:\Program Files\Google\Google Toolbar\Component\fastsearch_A8904FB862BD9564.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Program Files\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O4 - HKLM\..\Run: [COMODO Internet Security] "C:\Program Files\COMODO\COMODO Internet Security\cfp.exe" -h
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\Windows Live\Messenger\msnmsgr.exe" /background
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~3\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~3\Office12\EXCEL.EXE/3000
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~3\Office12\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\MSMSGS.EXE
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\MSMSGS.EXE
O14 - IERESET.INF: START_PAGE_URL=http://www.files-ftp.com/~unicorni/phpBB2/index.php
O16 - DPF: {2D8ED06D-3C30-438B-96AE-4D110FDC1FB8} (ActiveScan 2.0 Installer Class) - http://acs.pandasoftware.com/activescan/cabs/as2stubie.cab
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://download.bitdefender.com/resources/scanner/sources/en/scan8/oscan8.cab
O16 - DPF: {BB21F850-63F4-4EC9-BF9D-565BD30C9AE9} (a-squared Scanner) - http://ax.emsisoft.com/asquared.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{A604A122-4835-49B4-AC71-52B3B261CC27}: NameServer = 62.251.229.223 62.251.229.237
O18 - Filter: x-sdch - {B1759355-3EEC-4C1E-B0F1-B719FE26E377} - C:\Program Files\Google\Google Toolbar\Component\fastsearch_A8904FB862BD9564.dll
O20 - AppInit_DLLs: C:\WINDOWS\system32\guard32.dll
O23 - Service: C-DillaSrv - C-Dilla Ltd - C:\WINDOWS\system32\DRIVERS\CDANTSRV.EXE
O23 - Service: COMODO Internet Security Helper Service (cmdAgent) - COMODO - C:\Program Files\COMODO\COMODO Internet Security\cmdagent.exe
O23 - Service: Service Google Update (gupdate1c9c358a1f67cd6) (gupdate1c9c358a1f67cd6) - 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: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Program Files\Java\jre6\bin\jqs.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: TuneUp Drive Defrag Service (TuneUp.Defrag) - TuneUp Software - C:\WINDOWS\System32\TuneUpDefragService.exe
O23 - Service: TuneUp Program Statistics Service (TuneUp.ProgramStatisticsSvc) - TuneUp Software - C:\WINDOWS\System32\TUProgSt.exe