Comment se débarrasser de ce trojan ?

Bonjour,

J'aimerais demander de l'aide pour me débarrasser d'un trojan apparu depuis peu sur mon ordinateur. Le sujet a en fait déjà été traité sur ce forum, néanmoins n'y connaissant rien à l'analyse des rapport Hijackthis ou autres, je ne suis pas sur si la solution est la même pour tout le monde. Bref, je pose ma question tout de même...

Le trojan en question apparaît sous 2 formes:

1)une fenêtre où apparaît trojandownloader.xs et qui propose d'acheter un anti-spyware sur le lien suivant: http://antispyware-reviews.biz/?wmid=4663&pwebmid=R3n1c2Bg8A

2) une fenêtre intitulée 'System Security Warning' où on peut soi-disant installer un programme sécuritaire.

J'ai fait une analyse Hijackthis (voir ci-dessous), fait des analyses avec AVG 7.5, CC Cleaner, Ad-aware, SmitfraudFix, ainsi qu'avec mon anti-virus Avast version 4.7 home (le tout en mode sans-échec). Mais rien n'y fait, ce sale trojan n'est pas parti.

Je vous serais infiniment reconnaissant si vous pouviez m'aider. Voici l'analyse Hijackthis. Merci d'avance !

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 16:41:59, on 01.04.2008
Platform: Windows Vista (WinNT 6.00.1904)
MSIE: Internet Explorer v7.00 (7.00.6000.16609)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskeng.exe
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\Program Files\HP\QuickPlay\QPService.exe
C:\Program Files\HP\HP Software Update\hpwuSchd2.exe
C:\Program Files\Hewlett-Packard\HP Quick Launch Buttons\QLBCTRL.exe
C:\Program Files\Hewlett-Packard\HP Wireless Assistant\WiFiMsg.exe
C:\Program Files\Hewlett-Packard\HP Wireless Assistant\HPWAMain.exe
C:\Program Files\Java\jre1.6.0\bin\jusched.exe
C:\Program Files\Alwil Software\Avast4\ashDisp.exe
C:\Windows\System32\rundll32.exe
C:\Program Files\Common Files\Real\Update_OB\realsched.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\Program Files\Windows Sidebar\sidebar.exe
C:\Windows\ehome\ehtray.exe
C:\Program Files\Windows Live\Messenger\msnmsgr.exe
C:\ProgramData\wraxirur\arahylcr.exe
C:\ProgramData\nbwabsdz\lyrqxoxk.exe
C:\Program Files\WIDCOMM\Bluetooth Software\BTTray.exe
C:\Windows\ehome\ehmsas.exe
C:\Program Files\Windows Sidebar\sidebar.exe
C:\Program Files\WIDCOMM\Bluetooth Software\BtStackServer.exe
C:\PROGRA~1\HEWLET~1\Shared\HPQTOA~1.EXE
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\Microsoft Office\OFFICE11\WINWORD.EXE
C:\Program Files\mIRC\mirc.exe
C:\Program Files\Internet Explorer\IEUser.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Common Files\Microsoft Shared\Windows Live\WLLoginProxy.exe
C:\Users\Marcus\Desktop\HiJackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - URLSearchHook: SweetIM For Internet Explorer - {BC4FFE41-DE9F-46fa-B455-AAD49B9F9938} - C:\Program Files\Macrogaming\SweetIMBarForIE\toolbar.dll (file missing)
O1 - Hosts: ::1 localhost
O2 - BHO: Aide pour le lien d'Adobe PDF Reader - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: PC-Antispyware Site Blocker Button - {10F0C2A9-8E38-43e3-204D-45524C494E20} - C:\Program Files\PC-Antispyware\IeExtension.dll (file missing)
O2 - BHO: SWEETIE - {1A0AADCD-3A72-4b5f-900F-E3BB5A838E2A} - C:\PROGRA~1\MACROG~1\SWEETI~1\toolbar.dll (file missing)
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0\bin\ssv.dll
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\program files\google\googletoolbar2.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\program files\google\googletoolbar2.dll
O3 - Toolbar: SweetIM For Internet Explorer - {BC4FFE41-DE9F-46fa-B455-AAD49B9F9938} - C:\Program Files\Macrogaming\SweetIMBarForIE\toolbar.dll (file missing)
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [QPService] "C:\Program Files\HP\QuickPlay\QPService.exe"
O4 - HKLM\..\Run: [HP Software Update] C:\Program Files\Hp\HP Software Update\HPWuSchd2.exe
O4 - HKLM\..\Run: [QlbCtrl] %ProgramFiles%\Hewlett-Packard\HP Quick Launch Buttons\QlbCtrl.exe /Start
O4 - HKLM\..\Run: [HP Health Check Scheduler] C:\Program Files\Hewlett-Packard\HP Health Check\HPHC_Scheduler.exe
O4 - HKLM\..\Run: [WAWifiMessage] %ProgramFiles%\Hewlett-Packard\HP Wireless Assistant\WiFiMsg.exe
O4 - HKLM\..\Run: [hpWirelessAssistant] %ProgramFiles%\Hewlett-Packard\HP Wireless Assistant\HPWAMain.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0\bin\jusched.exe"
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [NvSvc] RUNDLL32.EXE C:\Windows\system32\nvsvc.dll,nvsvcStart
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\Windows\system32\NvCpl.dll,NvStartup
O4 - HKLM\..\Run: [NvMediaCenter] RUNDLL32.EXE C:\Windows\system32\NvMcTray.dll,NvTaskbarInit
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Common Files\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKLM\..\RunOnce: [Launcher] %WINDIR%\SMINST\launcher.exe
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [ISUSPM Startup] C:\PROGRA~1\COMMON~1\INSTAL~1\UPDATE~1\isuspm.exe -startup
O4 - HKCU\..\Run: [ehTray.exe] C:\Windows\ehome\ehTray.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\Windows Live\Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [hyzzrhew] C:\ProgramData\hyzzrhew\olwzolyv.exe
O4 - HKCU\..\Run: [JTQkUGder4] C:\ProgramData\wraxirur\arahylcr.exe
O4 - HKCU\..\Run: [nbwabsdz] C:\ProgramData\nbwabsdz\lyrqxoxk.exe
O4 - Global Startup: BTTray.lnk = ?
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~3\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: Envoyer au périphérique &Bluetooth... - btsendto_ie.htm
O8 - Extra context menu item: Envoyer l'&image au périphérique Bluetooth... - btsendto_ie_ctx.htm
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0\bin\ssv.dll
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~3\OFFICE11\REFIEBAR.DLL
O9 - Extra button: @btrez.dll,-4015 - {CCA281CA-C863-46ef-9331-5C8D4460577F} - btsendto_ie.htm (file missing)
O9 - Extra 'Tools' menuitem: @btrez.dll,-12650 - {CCA281CA-C863-46ef-9331-5C8D4460577F} - btsendto_ie.htm (file missing)
O13 - Gopher Prefix:
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~1\COMMON~1\Skype\SKYPE4~1.DLL
O23 - Service: Ad-Aware 2007 Service (aawservice) - Lavasoft - C:\Program Files\Lavasoft\Ad-Aware 2007\aawservice.exe
O23 - Service: AddFiltr - Hewlett-Packard Development Company, L.P. - C:\Program Files\Hewlett-Packard\HP Quick Launch Buttons\AddFiltr.exe
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 - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
O23 - Service: avast! Web Scanner - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
O23 - Service: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: CyberLink Background Capture Service (CBCS) (CLCapSvc) - Unknown owner - C:\Program Files\HP\QuickPlay\Kernel\TV\CLCapSvc.exe
O23 - Service: CyberLink Task Scheduler (CTS) (CLSched) - Unknown owner - C:\Program Files\HP\QuickPlay\Kernel\TV\CLSched.exe
O23 - Service: Symantec Lic NetConnect service (CLTNetCnService) - Unknown owner - c:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe (file missing)
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: HP Health Check Service - Hewlett-Packard - C:\Program Files\Hewlett-Packard\HP Health Check\hphc_service.exe
O23 - Service: hpqwmiex - Hewlett-Packard Development Company, L.P. - C:\Program Files\Hewlett-Packard\Shared\hpqwmiex.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Roxio\Roxio MyDVD Basic v9\InstallShield\Driver\1050\Intel 32\IDriverT.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: LiveUpdate - Symantec Corporation - C:\PROGRA~1\Symantec\LIVEUP~1\LUCOMS~1.EXE
O23 - Service: Planificateur LiveUpdate automatique - Symantec Corporation - C:\Program Files\Symantec\LiveUpdate\ALUSchedulerSvc.exe
O23 - Service: RoxMediaDB9 - Sonic Solutions - C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxMediaDB9.exe
O23 - Service: stllssvr - MicroVision Development, Inc. - C:\Program Files\Common Files\SureThing Shared\stllssvr.exe
O23 - Service: XAudioService - Conexant Systems, Inc. - C:\Windows\system32\DRIVERS\xaudio.exe