Processus désorganisés

Bonjour,

J'ai un énorme probleme sur mon PC : comme le dit mon titre de sujet, mes processus font ce qu'ils veulent, iexplore a 350 000ko pour une page, explorer.exe a 20 000ko...
explorer.exe n'est plus assez puissant pour mon PC, et du coup je lag a mort tout le temps.
ma config: Intel pentium 4 (3.0 Ghz, non overclocké); carte graphique MSI NX6600 GT, 1GO ram...
Antivirus: Virusscan 8.0.0, version légale et PAYANTE, enregistré sur le site, mis a jour tous les jours

je poste avec un rapport hijack fait quelques minutes avant d'écrire ce poste:
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 16:23:32, on 08/10/2008
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16705)
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:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\Program Files\Network Associates\Common Framework\FrameworkService.exe
C:\Program Files\Network Associates\VirusScan\Mcshield.exe
C:\Program Files\Network Associates\VirusScan\VsTskMgr.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Program Files\Network Associates\VirusScan\SHSTAT.EXE
C:\Program Files\Network Associates\Common Framework\UpdaterUI.exe
C:\Program Files\Fichiers communs\Network Associates\TalkBack\TBMon.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\PROGRA~1\PANICW~1\POP-UP~1\PSFree.exe
C:\Program Files\SpeedFan\speedfan.exe
C:\Program Files\VideoLAN\VLC\vlc.exe
C:\Program Files\Windows Live\Messenger\usnsvc.exe
C:\Documents and Settings\Guillaume\Mes documents\Guitou\Logiciels\HiJackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.fr/?gws_rd=ssl
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Internet Explorer avec Club-Internet
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: ContributeBHO Class - {074C1DC5-9320-4A9A-947D-C042949C6216} - C:\Program Files\Adobe\/Adobe Contribute CS3/contributeieplugin.dll
O2 - BHO: AcroIEHelperStub - {18DF081C-E8AD-4283-A596-FA578C2EBDC3} - C:\Program Files\Fichiers communs\Adobe\Acrobat\ActiveX\AcroIEHelperShim.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_06\bin\ssv.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
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
O3 - Toolbar: Contribute Toolbar - {517BDDE4-E3A7-4570-B21E-2B52B6139FC7} - C:\Program Files\Adobe\/Adobe Contribute CS3/contributeieplugin.dll
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [ShStatEXE] "C:\Program Files\Network Associates\VirusScan\SHSTAT.EXE" /STANDALONE
O4 - HKLM\..\Run: [McAfeeUpdaterUI] "C:\Program Files\Network Associates\Common Framework\UpdaterUI.exe" /StartedFromRunKey
O4 - HKLM\..\Run: [Network Associates Error Reporting Service] "C:\Program Files\Fichiers communs\Network Associates\TalkBack\TBMon.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 9.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [Adobe_ID0EYTHM] C:\PROGRA~1\FICHIE~1\Adobe\ADOBEV~1\Server\bin\VERSIO~2.EXE
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [PopUpStopperFreeEdition] C:\PROGRA~1\PANICW~1\POP-UP~1\PSFree.exe
O4 - HKCU\..\Run: [speedfan] C:\Program Files\SpeedFan\speedfan.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'Default user')
O4 - Startup: SpeedFan
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_06\bin\ssv.dll
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner v8 - {85d1f590-48f4-11d9-9669-0800200c9a66} - C:\WINDOWS\bdoscandel.exe
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
O10 - Unknown file in Winsock LSP: c:\windows\system32\nwprovau.dll
O10 - Broken Internet access because of LSP provider 'c:\program files\bonjour\mdnsnsp.dll' missing
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://www.bitdefender.fr/scan_fr/scan8/oscan8.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://www.update.microsoft.com/...
O16 - DPF: {8AD9C840-044E-11D1-B3E9-00805F499D93} (Java Runtime Environment 1.6.0) - http://dl8-cdn-01.sun.com/s/ESD42/JSCDL/jre/6u6-b90/jinstall-6u6-windows-i586-jc.cab?e=1213970184638&h=34e32685c5eb71477ab262c16073e13c/&filename=jinstall-6u6-windows-i586-jc.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{DDC3D55D-E9CF-4DEF-80CC-665367C9E529}: NameServer = 194.117.200.10,194.117.200.15
O23 - Service: Adobe Version Cue CS3 {fr_FR} (Adobe Version Cue CS3) - Adobe Systems Incorporated - C:\Program Files\Fichiers communs\Adobe\Adobe Version Cue CS3\Server\bin\VersionCueCS3.exe
O23 - Service: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: Service Framework McAfee (McAfeeFramework) - McAfee, Inc. - C:\Program Files\Network Associates\Common Framework\FrameworkService.exe
O23 - Service: Network Associates McShield (McShield) - Network Associates, Inc. - C:\Program Files\Network Associates\VirusScan\Mcshield.exe
O23 - Service: Network Associates Task Manager (McTaskManager) - Network Associates, Inc. - C:\Program Files\Network Associates\VirusScan\VsTskMgr.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 GmbH - C:\WINDOWS\System32\TuneUpDefragService.exe