Trojan Systeme error avec Vista

Bonjour,
Depuis peut quand j'ouvre un dossier windows vista m'envoy le message suivant :

Systeme error!
Your PC was infected by unknown trojan.
It's dangerous for your system (critical files can be lost) !
Click OK to download the antispyare program to clean your system ! (recommanded)


Je clic Ok mais rien ne change!J'ai fait des scan avec Avast,cclener,spybot C&D et ad-aware qui eux n'ont trouvé aucun trojan
comment faire SVP??

Analyse avec Hijackthis me donne ceci :

Lorsque je lance le scann Hijackthis menvoi le message suivant en plein milieu du scan!

"for some reason your systeme denied write access to the Host file. If any Hijacked domains are in this files, Hijacked may Not able to fix this.
If tha happens, you need to edit the file yourself. To do this, click star, run and type:
notpad C:\Windows\Systeme32\drivers\etc\hosts
and press enter. Fine the line(s) hijackthis reports ant delete them.
Save the file has "hosts."(with quotes), and reboot.

For Vista simply, simply exit Hijackthis, right click on Hijackthis icon, choose' run as administrator'"
Puis je clic sur Ok
Le scan se termine et j'obtien le rapport suivant :

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 05:46:42, on 06/01/2008
Platform: Windows Vista (WinNT 6.00.1904)
MSIE: Internet Explorer v7.00 (7.00.6000.16575)
Boot mode: Normal

Running processes:
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxWatchTray9.exe
C:\Program Files\Roxio\Media Experience\DMXLauncher.exe
C:\Program Files\Roxio\Drag-to-Disc\DrgToDsc.exe
C:\Windows\RtHDVCpl.exe
C:\Windows\System32\rundll32.exe
C:\Program Files\Alwil Software\Avast4\ashDisp.exe
C:\Program Files\Lavasoft\Ad-Aware 2007\AAWTray.exe
C:\Program Files\Java\jre1.6.0_03\bin\jusched.exe
C:\Windows\System32\rundll32.exe
C:\Program Files\Windows Sidebar\sidebar.exe
C:\Windows\ehome\ehtray.exe
C:\Program Files\Google\GoogleToolbarNotifier\1.2.1128.5462\GoogleToolbarNotifier.exe
C:\Windows\System32\p2phost.exe
C:\Program Files\Windows Live\Messenger\msnmsgr.exe
C:\Windows\ehome\ehmsas.exe
C:\Windows\system32\taskeng.exe
C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\CPSHelpRunner.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\HiJackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.fr/?gws_rd=ssl
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = https://www.msn.com/fr-fr/?ocid=iehp
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr/?ocid=iehp
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - URLSearchHook: Search Class - {08C06D61-F1F3-4799-86F8-BE1A89362C85} - C:\Program Files\OrangeHSS\SearchURLHook\SearchPageURL.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: Spybot-S&D IE Protection - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.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 Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\program files\google\googletoolbar1.dll
O2 - BHO: Rates - {F325C9B7-4876-4665-895B-674D657645C2} - C:\Windows\toprates.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\program files\google\googletoolbar1.dll
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [RoxWatchTray] "C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxWatchTray9.exe"
O4 - HKLM\..\Run: [DMXLauncher] "C:\Program Files\Roxio\Media Experience\DMXLauncher.exe"
O4 - HKLM\..\Run: [RoxioDragToDisc] "C:\Program Files\Roxio\Drag-to-Disc\DrgToDsc.exe"
O4 - HKLM\..\Run: [RtHDVCpl] RtHDVCpl.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: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [AAWTray] C:\Program Files\Lavasoft\Ad-Aware 2007\AAWTray.exe
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_03\bin\jusched.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [SystrayORAHSS] "C:\Program Files\OrangeHSS\Systray\SystrayApp.exe"
O4 - HKCU\..\Run: [Sidebar] C:\Program Files\Windows Sidebar\sidebar.exe /autoRun
O4 - HKCU\..\Run: [ehTray.exe] C:\Windows\ehome\ehTray.exe
O4 - HKCU\..\Run: [swg] C:\Program Files\Google\GoogleToolbarNotifier\1.2.1128.5462\GoogleToolbarNotifier.exe
O4 - HKCU\..\Run: [CollaborationHost] C:\Windows\system32\p2phost.exe -s
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\Windows Live\Messenger\MsnMsgr.Exe" /background
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.dll
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O13 - Gopher Prefix:
O16 - DPF: {67DABFBF-D0AB-41FA-9C46-CC0F21721616} (DivXBrowserPlugin Object) - http://download.divx.com/player/DivXBrowserPlugin.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O23 - Service: Ad-Aware 2007 Service (aawservice) - Lavasoft AB - C:\Program Files\Lavasoft\Ad-Aware 2007\aawservice.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: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\1050\Intel 32\IDriverT.exe
O23 - Service: Roxio UPnP Renderer 9 - Sonic Solutions - C:\Program Files\Common Files\Sonic Shared\RoxioUPnPRenderer9.exe
O23 - Service: Roxio Upnp Server 9 - Sonic Solutions - C:\Program Files\Common Files\Sonic Shared\RoxioUpnpService9.exe
O23 - Service: LiveShare P2P Server 9 (RoxLiveShare9) - Sonic Solutions - C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxLiveShare9.exe
O23 - Service: RoxMediaDB9 - Sonic Solutions - C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxMediaDB9.exe
O23 - Service: Roxio Hard Drive Watcher 9 (RoxWatch9) - Sonic Solutions - C:\Program Files\Common Files\Roxio Shared\9.0\SharedCOM\RoxWatch9.exe
O23 - Service: stllssvr - MicroVision Development, Inc. - C:\Program Files\Common Files\SureThing Shared\stllssvr.exe