Probleme de pub qui s'ouvre sans arret

bonjour a tous et merci d'avance pour toute les reponses que vous pourrais m'apporté,
j'ai un probleme de pub d'anti-virus qui souvre tout le temps.

j'ai fait un scan avec hijackthis dont voici le rapport :

Logfile of HijackThis v1.99.1
Scan saved at 03:39:10, on 23/08/2007
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:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\Program Files\WIDCOMM\Logiciel Bluetooth\bin\btwdins.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\WistitiSoft\Agent.exe
C:\Program Files\QuickTime\qttask.exe
C:\Program Files\Skype\Phone\Skype.exe
C:\Program Files\Mio Technology\MioSync\mioSync.exe
C:\Program Files\Eurobarre\eb.exe
C:\Program Files\Skype\Plugin Manager\SkypePM.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\DVD Shrink\DVD Shrink 3.2.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\Hijackthis Version Française\hijackthis vf.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = https://www.bing.com/?cc=fr&toHttps=1&redig=D4322FEE7CF74A348CB9CE970F098EF5
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr
R3 - Default URLSearchHook is missing
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: (no name) - {8d83b16e-0de1-452b-ac52-96ec0b34aa4b} - (no file)
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [ExtraFilmHemmaAgent] "C:\Program Files\WistitiSoft\Agent.exe"
O4 - HKLM\..\Run: [nwiz] nwiz.exe /install
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\WINDOWS\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKCU\..\Run: [X'nBeep] C:\Program Files\X'nBeep 1.1\XnBeep.exe
O4 - HKCU\..\Run: [Skype] "C:\Program Files\Skype\Phone\Skype.exe" /nosplash /minimized
O4 - Startup: Eurobarre.lnk = C:\Program Files\Eurobarre\eb.exe
O4 - Global Startup: MioSync.lnk = C:\Program Files\Mio Technology\MioSync\mioSync.exe
O17 - HKLM\System\CCS\Services\Tcpip\..\{6CC323C1-0289-4B3A-8A4A-B35AFA36F52C}: NameServer = 84.103.237.146 86.64.145.146
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~1\FICHIE~1\Skype\SKYPE4~1.DLL
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\
O20 - Winlogon Notify: winmqx32 - C:\WINDOWS\
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: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: Bluetooth Service (btwdins) - WIDCOMM, Inc. - C:\Program Files\WIDCOMM\Logiciel Bluetooth\bin\btwdins.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Logitech Process Monitor (LVPrcSrv) - Unknown owner - (no file)
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe

merci de peut-etre pouvoir m'aider....