Probleme de forte utilisation processeur

bonjour,
j ai un petit soucis depuis qq jours,mon pc marche au ralenti .
j ai reformaté mon pc il y a 1 mois ,je possede mc afee comme antivirus et comme firewall .
dans le gestionnaire des taches j ai remarqué que l utilisation processeur s emballait meme avec tres peu d activités, j ai remarqué que Mcshield.exe a tendance a s' emballé au niveau de l utilisation processeur .je ne sais pas si cela a quelquechose a voir .
voici mon log , j'espère que qq1 pourra m aider je lui en serait très reconnaissant car la je ne trouve pas de solution .
1000 merci par avance pour vos réponses .

Logfile of HijackThis v1.99.1
Scan saved at 22:15:23, on 23/02/2006
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
c:\program files\mcafee.com\agent\mcdetect.exe
c:\PROGRA~1\mcafee.com\vso\mcshield.exe
c:\PROGRA~1\mcafee.com\agent\mctskshd.exe
c:\PROGRA~1\mcafee.com\vso\OasClnt.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MpfService.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\system32\svchost.exe
C:\PROGRA~1\mcafee.com\vso\mcvsshld.exe
c:\program files\mcafee.com\agent\mcagent.exe
c:\progra~1\mcafee.com\vso\mcvsescn.exe
C:\WINDOWS\system32\RUNDLL32.EXE
C:\WINDOWS\Mixer.exe
C:\Program Files\Microsoft AntiSpyware\gcasServ.exe
C:\Program Files\Java\jre1.5.0_06\bin\jusched.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MpfTray.exe
C:\Program Files\Microsoft AntiSpyware\gcasDtServ.exe
C:\PROGRA~1\McAfee.com\PERSON~1\MpfAgent.exe
C:\WINDOWS\BricoPacks\Vista Inspirat\YzToolbar\YzToolBar.exe
C:\WINDOWS\system32\taskmgr.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\XP Tools\xptools.exe
C:\Program Files\XP Tools\xptools.exe
C:\Documents and Settings\Admin\Bureau\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = about:blank
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://www.google.fr/
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
R3 - Default URLSearchHook is missing
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Program Files\Spybot - Search & Destroy\SDHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O3 - Toolbar: McAfee VirusScan - {BA52B914-B692-46c4-B683-905236F6F655} - c:\progra~1\mcafee.com\vso\mcvsshl.dll
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [VSOCheckTask] "C:\PROGRA~1\McAfee.com\VSO\mcmnhdlr.exe" /checktask
O4 - HKLM\..\Run: [VirusScan Online] C:\Program Files\McAfee.com\VSO\mcvsshld.exe
O4 - HKLM\..\Run: [OASClnt] C:\Program Files\McAfee.com\VSO\oasclnt.exe
O4 - HKLM\..\Run: [MCAgentExe] c:\PROGRA~1\mcafee.com\agent\mcagent.exe
O4 - HKLM\..\Run: [MCUpdateExe] c:\PROGRA~1\mcafee.com\agent\mcupdate.exe
O4 - HKLM\..\Run: [C-Media Mixer] Mixer.exe /startup
O4 - HKLM\..\Run: [gcasServ] "C:\Program Files\Microsoft AntiSpyware\gcasServ.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] C:\Program Files\Java\jre1.5.0_06\bin\jusched.exe
O4 - HKLM\..\Run: [MPFExe] C:\PROGRA~1\McAfee.com\PERSON~1\MpfTray.exe
O4 - HKCU\..\Run: [XP Tools] C:\Program Files\XP Tools\xptools.exe /min
O4 - Startup: Stardock ObjectDock.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat\ObjectDock\ObjectDock.exe
O4 - Startup: Y'z ToolBar.lnk = C:\WINDOWS\BricoPacks\Vista Inspirat\YzToolbar\YzToolBar.exe
O4 - Global Startup: Adobe Gamma Loader.lnk = C:\Program Files\Fichiers communs\Adobe\Calibration\Adobe Gamma Loader.exe
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~3\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~3\OFFICE11\REFIEBAR.DLL
O16 - DPF: {4ED9DDF0-7479-4BBE-9335-5A1EDB1D8A21} (McAfee.com Operating System Class) - http://download.mcafee.com/molbin/shared/mcinsctl/4,0,0,101/mcinsctl.cab
O16 - DPF: {4F1E5B1A-2A80-42CA-8532-2D05CB959537} (MSN Photo Upload Tool) - http://spaces.msn.com//PhotoUpload/MsnPUpld.cab
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O23 - Service: Adobe LM Service - Unknown owner - C:\Program Files\Fichiers communs\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: McAfee WSC Integration (McDetect.exe) - McAfee, Inc - c:\program files\mcafee.com\agent\mcdetect.exe
O23 - Service: McAfee.com McShield (McShield) - McAfee Inc. - c:\PROGRA~1\mcafee.com\vso\mcshield.exe
O23 - Service: McAfee Task Scheduler (McTskshd.exe) - McAfee, Inc - c:\PROGRA~1\mcafee.com\agent\mctskshd.exe
O23 - Service: McAfee SecurityCenter Update Manager (mcupdmgr.exe) - McAfee, Inc - C:\PROGRA~1\McAfee.com\Agent\mcupdmgr.exe
O23 - Service: McAfee Personal Firewall Service (MpfService) - McAfee Corporation - C:\PROGRA~1\McAfee.com\PERSON~1\MpfService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: StarWind iSCSI Service (StarWindService) - Rocket Division Software - C:\Program Files\Alcohol Soft\Alcohol 120\StarWind\StarWindService.exe