Ok merci beaucoup pour vos précieuses informations.
Pour ce qui est du scan hijackthis voici le rapport :
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 09:03:16, on 24/07/2008
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16674)
Boot mode: Normal
Running processes:
C:WINDOWSSystem32smss.exe
C:WINDOWSsystem32winlogon.exe
C:WINDOWSsystem32services.exe
C:WINDOWSsystem32lsass.exe
C:WINDOWSsystem32svchost.exe
C:WINDOWSSystem32svchost.exe
C:Program FilesAlwil SoftwareAvast4aswUpdSv.exe
C:Program FilesAlwil SoftwareAvast4ashServ.exe
C:WINDOWSExplorer.EXE
C:WINDOWSsystem32spoolsv.exe
C:PROGRA~1ALWILS~1Avast4ashDisp.exe
C:WINDOWSsystem32RUNDLL32.EXE
C:Program FilesWinampwinampa.exe
C:WINDOWSsystem32RunDll32.exe
C:Program FilesRazerKrait
azerhid.exe
C:WINDOWSsystem32LVCOMSX.EXE
C:Program FilesLogitechVideoLogiTray.exe
C:WINDOWSsystem32ctfmon.exe
C:Program FilesGoogleGoogleToolbarNotifier1.2.1128.5462GoogleToolbarNotifier.exe
C:Program FilesSpybot - Search & DestroyTeaTimer.exe
C:Program FilesRazerKrait
azerofa.exe
C:Program FilesLogitechVideoFxSvr2.exe
C:WINDOWSSystem32svchost.exe
C:Program FilesAlwil SoftwareAvast4ashMaiSv.exe
C:Program FilesAlwil SoftwareAvast4ashWebSv.exe
C:Program FilesInternet Exploreriexplore.exe
C:Program FilesFichiers communsMicrosoft SharedWindows LiveWLLoginProxy.exe
C:Program FilesTrend MicroHijackThisHijackThis.exe
R0 - HKCUSoftwareMicrosoftInternet ExplorerMain,Start Page =
http://www.orange.fr/
R1 - HKLMSoftwareMicrosoftInternet ExplorerMain,Default_Page_URL =
http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLMSoftwareMicrosoftInternet ExplorerMain,Default_Search_URL =
http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLMSoftwareMicrosoftInternet ExplorerMain,Search Page =
http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLMSoftwareMicrosoftInternet ExplorerMain,Start Page =
http://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKCUSoftwareMicrosoftInternet ExplorerToolbar,LinksFolderName = Liens
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:Program FilesAdobeAcrobat 5.0ReaderActiveXAcroIEHelper.ocx
O2 - BHO: Spybot-S&D IE Protection - {53707962-6F74-2D53-2644-206D7942484F} - C:PROGRA~1SPYBOT~1SDHelper.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 FilesFichiers communsMicrosoft SharedWindows LiveWindowsLiveLogin.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:program filesgooglegoogletoolbar2.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:program filesgooglegoogletoolbar2.dll
O4 - HKLM..Run: [avast!] C:PROGRA~1ALWILS~1Avast4ashDisp.exe
O4 - HKLM..Run: [NvCplDaemon] RUNDLL32.EXE C:WINDOWSsystem32NvCpl.dll,NvStartup
O4 - HKLM..Run: [nwiz] nwiz.exe /install
O4 - HKLM..Run: [NvMediaCenter] RUNDLL32.EXE C:WINDOWSsystem32NvMcTray.dll,NvTaskbarInit
O4 - HKLM..Run: [WinampAgent] "C:Program FilesWinampwinampa.exe"
O4 - HKLM..Run: [Cmaudio] RunDll32 cmicnfg.cpl,CMICtrlWnd
O4 - HKLM..Run: [Krait] C:Program FilesRazerKrait
azerhid.exe
O4 - HKLM..Run: [LVCOMSX] C:WINDOWSsystem32LVCOMSX.EXE
O4 - HKLM..Run: [LogitechVideoRepair] C:Program FilesLogitechVideoISStart.exe
O4 - HKLM..Run: [LogitechVideoTray] C:Program FilesLogitechVideoLogiTray.exe
O4 - HKCU..Run: [CTFMON.EXE] C:WINDOWSsystem32ctfmon.exe
O4 - HKCU..Run: [swg] C:Program FilesGoogleGoogleToolbarNotifier1.2.1128.5462GoogleToolbarNotifier.exe
O4 - HKCU..Run: [LogitechSoftwareUpdate] "C:Program FilesLogitechVideoManifestEngine.exe" boot
O4 - HKCU..Run: [SpybotSD TeaTimer] C:Program FilesSpybot - Search & DestroyTeaTimer.exe
O4 - HKUSS-1-5-19..Run: [CTFMON.EXE] C:WINDOWSSystem32CTFMON.EXE (User 'SERVICE LOCAL')
O4 - HKUSS-1-5-20..Run: [CTFMON.EXE] C:WINDOWSSystem32CTFMON.EXE (User 'SERVICE RESEAU')
O4 - HKUSS-1-5-18..Run: [CTFMON.EXE] C:WINDOWSSystem32CTFMON.EXE (User 'SYSTEM')
O4 - HKUS.DEFAULT..Run: [CTFMON.EXE] C:WINDOWSSystem32CTFMON.EXE (User 'Default user')
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:PROGRA~1SPYBOT~1SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:PROGRA~1SPYBOT~1SDHelper.dll
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:WINDOWSNetwork Diagnosticxpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:WINDOWSNetwork Diagnosticxpnetdiag.exe
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:Program FilesMessengermsmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:Program FilesMessengermsmsgs.exe
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:Program FilesAlwil SoftwareAvast4aswUpdSv.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:Program FilesAlwil SoftwareAvast4ashServ.exe
O23 - Service: avast! Mail Scanner - ALWIL Software - C:Program FilesAlwil SoftwareAvast4ashMaiSv.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:Program FilesAlwil SoftwareAvast4ashWebSv.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:Program FilesGoogleCommonGoogle UpdaterGoogleUpdaterService.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:WINDOWSsystem32
vsvc32.exe
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End of file - 5742 bytes