Processus indésirables, virus ?

Bonjour à tous,

Je viens quérir votre aide car il me semble que j'ai certains processus indésirables car à peine mon ordinateur allumé, 202 MB de ram pris...
Donc je me demandais que si je donnais mon log hijackthis quelqu'un pourrait m'aider certains éventuels virus... :)

Logfile of HijackThis v1.99.1
Scan saved at 19:03:10, on 25/09/2008
Platform: Windows XP SP3, v.5512 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.20772)

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\svchost.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\NVIDIA Corporation\nTune\nTuneService.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\Program Files\NVIDIA Corporation\System Update\UpdateCenterService.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\802.11 Wireless LAN\802.11g Wireless CardBus & PCI Adapter HW.15 V.1.00\WlanCU.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\Alwil Software\Avast4\setup\avast.setup
C:\WINDOWS\system32\svchost.exe
C:\HiJackThis\HijackThis.exe

O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe"
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\RunOnce: [WIAWizardMenu] RUNDLL32.EXE C:\WINDOWS\system32\sti_ci.dll,WiaCreateWizardMenu
O4 - HKCU\..\Run: [NVIDIA nTune] C:\Program Files\NVIDIA Corporation\nTune\nTuneCmd.exe resetprofile
O4 - Global Startup: Microsoft Office.lnk = C:\Program Files\Microsoft Office\Office\OSA9.EXE
O4 - Global Startup: Wireless Configuration Utility HW.15.lnk = C:\Program Files\802.11 Wireless LAN\802.11g Wireless CardBus & PCI Adapter HW.15 V.1.00\WlanCU.exe
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\WINDOWS\system32\shdocvw.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\WINDOWS\system32\shdocvw.dll
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O11 - Options group: [INTERNATIONAL] International*
O11 - Options group: [TABS] Tabbed Browsing
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\WINDOW~3\MESSEN~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\WINDOW~3\MESSEN~1\MSGRAP~1.DLL
O20 - Winlogon Notify: dimsntfy - %SystemRoot%\System32\dimsntfy.dll (file missing)
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\wpdshserviceobj.dll
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: Performance Service (nTuneService) - NVIDIA - C:\Program Files\NVIDIA Corporation\nTune\nTuneService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: Update Center Service (UpdateCenterService) - NVIDIA - C:\Program Files\NVIDIA Corporation\System Update\UpdateCenterService.exe

voilà j'espère que quelqu'un sera apte à me donner plus amples informations, merci d'avance et à bientôt :)