Comment enlever virus detecté par avast

Bonjour,
Depuis 2/3 semaines, j'ai un virus sur mon ordinateur. Avast (version gratuite) qui est mon logiciel anti-virus, dit bloquer divers virus (j'ai déjà eut un cheval de Troie et un droper), mais des pubs s'affichent souvent.
Voici ci dessous ce que ca donne avec hijackthis :
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 19:42:21, on 24/04/2011
Platform: Windows Vista SP2 (WinNT 6.00.1906)
MSIE: Internet Explorer v8.00 (8.00.6001.19019)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Windows\system32\taskeng.exe
C:\Program Files\Alwil Software\Avast5\AvastUI.exe
C:\Windows\System32\cc32\webtmr.exe
C:\Program Files\Common Files\Java\Java Update\jusched.exe
C:\Windows\System32\mobsync.exe
C:\Program Files\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe
C:\Windows\tray\wintmr.exe
C:\Program Files\Meilleur coupon\meilleurcoupon.exe
C:\Program Files\Windows Defender\MSASCui.exe
C:\Windows\system32\wuauclt.exe
C:\Program Files\Mozilla Firefox 4.0 Beta 12\firefox.exe
C:\Program Files\Mozilla Firefox 4.0 Beta 12\firefox.exe
C:\Program Files\Mozilla Firefox 4.0 Beta 12\plugin-container.exe
C:\Program Files\Mozilla Firefox 4.0 Beta 12\firefox.exe
C:\Users\Travers-Portable-2\Downloads\HiJackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.gateway.com/... E510
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://vshare.toolbarhome.com/?hp=df
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.gateway.com/... E510
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.gateway.com/... E510
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://www.gateway.com/... E510
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: TBSB01620 - {58124A0B-DC32-4180-9BFF-E0E21AE34026} - C:\Program Files\IMinent Toolbar\tbcore3.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O2 - BHO: Google Toolbar Notifier BHO - {AF69DE43-7D58-4638-B6FA-CE66B5AD205D} - C:\Program Files\Google\GoogleToolbarNotifier\5.6.6209.1142\swg.dll
O2 - BHO: Browser Address Error Redirector - {CA6319C0-31B7-401E-A518-A07C3DB8F777} - c:\windows\system32\BAE.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O3 - Toolbar: Google Toolbar - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - C:\Program Files\Google\Google Toolbar\GoogleToolbar_32.dll
O3 - Toolbar: IMinent Toolbar - {977AE9CC-AF83-45E8-9E03-E2798216E2D5} - C:\Program Files\IMinent Toolbar\tbcore3.dll
O4 - HKLM\..\Run: [avast5] "C:\Program Files\Alwil Software\Avast5\avastUI.exe" /nogui
O4 - HKLM\..\Run: [ChicoSys] C:\Windows\system32\cc32\webtmr.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Common Files\Java\Java Update\jusched.exe"
O4 - HKLM\..\Run: [IMBooster] C:\Program Files\Iminent\IMBooster\IMBooster.exe /warmup
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKCU\..\Run: [swg] "C:\Program Files\Google\GoogleToolbarNotifier\GoogleToolbarNotifier.exe"
O4 - HKCU\..\Run: [CCWinTray] C:\Windows\Tray\wintmr.exe
O4 - HKCU\..\Run: [Oxeperulatoqez] rundll32.exe "C:\Users\Travers-Portable-2\AppData\Local\soIRer.dll",Startup
O4 - HKLM\..\Policies\Explorer\Run: [1ay9e1] C:\Windows\TEMP\7em1.exe
O4 - Startup: meilleurcoupon687117254.lnk = C:\Program Files\Meilleur coupon\meilleurcoupon.exe
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office12\EXCEL.EXE/3000
O8 - Extra context menu item: Google Sidewiki... - res://C:\Program Files\Google\Google Toolbar\Component\GoogleToolbarDynamic_mui_en_D183CA64F05FDD98.dll/cmsidewiki.html
O9 - Extra button: Envoyer à OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra 'Tools' menuitem: &Envoyer à OneNote - {2670000A-7350-4f3c-8081-5663EE0C6C49} - C:\PROGRA~1\MICROS~2\Office12\ONBttnIE.dll
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\Office12\REFIEBAR.DLL
O13 - Gopher Prefix:
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O16 - DPF: {E2883E8F-472F-4FB0-9522-AC9BF37916A7} - http://platformdl.adobe.com/NOS/getPlusPlus/1.6/gp.cab
O20 - AppInit_DLLs: C:\PROGRA~1\Google\GOOGLE~1\GOEC62~1.DLL
O23 - Service: AMService - Unknown owner - C:\Windows\TEMP\xgdm\setup.exe (file missing)
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Common Files\Apple\Mobile Device Support\AppleMobileDeviceService.exe
O23 - Service: avast! Antivirus - AVAST Software - C:\Program Files\Alwil Software\Avast5\AvastSvc.exe
O23 - Service: Service Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Intel(R) Matrix Storage Event Monitor (IAANTMON) - Intel Corporation - C:\Program Files\Intel\Intel Matrix Storage Manager\Iaantmon.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\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: MouseDriver - Unknown owner - C:\Windows\TEMP\MouseDriver.bat (file missing)
O23 - Service: ServiceLayer - Nokia. - C:\Program Files\PC Connectivity Solution\ServiceLayer.exe
O23 - Service: Windows-CCHook-Service - Salfeld Computer - C:\Windows\system32\cchservice.exe