Bonjour,
mon ordinateur est infecté depuis deux jours par plusieurs chevaux de troie via msn.
J'ai regardé plusieurs conseils déjà postés et voici le rapport d'erreur établi via Hijack:

Logfile of HijackThis v1.99.1
Scan saved at 10:12:19, on 06/10/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16512)

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\ibmpmsvc.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\ThinkPad\PkgMgr\HOTKEY\TPHKMGR.exe
C:\WINDOWS\AGRSMMSG.exe
C:\Program Files\Synaptics\SynTP\SynTPLpr.exe
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\WINDOWS\system32\RunDll32.exe
C:\Program Files\Network Associates\VirusScan\SHSTAT.EXE
C:\Program Files\Network Associates\Common Framework\UpdaterUI.exe
C:\Program Files\Neuf\Kit\WiFi\9wifi.exe
C:\Program Files\Fichiers communs\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
C:\WINDOWS\System32\Ati2evxx.exe
D:\Logiciels\iTunesHelper.exe
C:\Documents and Settings\Administrateur\Bureau\AVG Anti-Spyware 7.5\guard.exe
C:\Documents and Settings\Administrateur\Bureau\AVG Anti-Spyware 7.5\avgas.exe
C:\Program Files\Fichiers communs\EPSON\EBAPI\SAgent2.exe
C:\Program Files\Network Associates\Common Framework\FrameworkService.exe
C:\Program Files\Network Associates\VirusScan\Mcshield.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\MSN Messenger\msnmsgr.exe
C:\Program Files\Skype\Phone\Phone\Skype.exe
C:\Program Files\Network Associates\VirusScan\VsTskMgr.exe
C:\Program Files\Fichiers communs\Microsoft Shared\VS7Debug\mdm.exe
C:\WINDOWS\System32\NMSSvc.exe
C:\WINDOWS\nts.exe
C:\WINDOWS\System32\QCONSVC.EXE
C:\WINDOWS\System32\svchost.exe
C:\Program Files\iPod\bin\iPodService.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Program Files\Internet Explorer\IEXPLORE.EXE
C:\Program Files\Hijackthis Version Française\hijackthis vf.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.9online.fr
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://recherche.neuf.fr/ie/default.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://recherche.neuf.fr/
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://french.icrfast.com/index.php?rvs=hompag
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://recherche.neuf.fr/
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://go.microsoft.com/fwlink/?LinkId=69157
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://recherche.neuf.fr/ie/default.html
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyServer = 142.34.1.4:8080
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = localhost;<local>
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
F2 - REG:system.ini: UserInit=C:\WINDOWS\system32\userinit.exe,c:\skew.exe
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 5.0\Reader\ActiveX\AcroIEHelper.ocx
O2 - BHO: (no name) - {4E7BD74F-2B8D-469E-C0FF-FD60B590A87D} - (no file)
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O3 - Toolbar: (no name) - {4E7BD74F-2B8D-469E-C0FF-FD60B590A87D} - (no file)
O4 - HKLM\..\Run: [TPHOTKEY] C:\PROGRA~1\ThinkPad\PkgMgr\HOTKEY\TPHKMGR.exe
O4 - HKLM\..\Run: [AGRSMMSG] AGRSMMSG.exe
O4 - HKLM\..\Run: [TP4EX] tp4ex.exe
O4 - HKLM\..\Run: [TrackPointSrv] tp4serv.exe
O4 - HKLM\..\Run: [SynTPLpr] C:\Program Files\Synaptics\SynTP\SynTPLpr.exe
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [BMMGAG] RunDll32 C:\PROGRA~1\ThinkPad\UTILIT~1\pwrmonit.dll,StartPwrMonitor
O4 - HKLM\..\Run: [ATIModeChange] Ati2mdxx.exe
O4 - HKLM\..\Run: [ShStatEXE] "C:\Program Files\Network Associates\VirusScan\SHSTAT.EXE" /STANDALONE
O4 - HKLM\..\Run: [McAfeeUpdaterUI] "C:\Program Files\Network Associates\Common Framework\UpdaterUI.exe" /StartedFromRunKey
O4 - HKLM\..\Run: [Autoconfigurateur WiFi Neuf] "C:\Program Files\Neuf\Kit\WiFi\9wifi.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [iTunesHelper] "D:\Logiciels\iTunesHelper.exe"
O4 - HKLM\..\Run: [Network Translation Service] "c:\skew.exe" *
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Documents and Settings\Administrateur\Bureau\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\msnmsgr.exe" /background
O4 - HKCU\..\Run: [Skype] "C:\Program Files\Skype\Phone\Phone\Skype.exe" /nosplash /minimized
O4 - HKCU\..\Run: [Network Translation Service] "c:\skew.exe" *
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\Office10\EXCEL.EXE/3000
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - %windir%\Network Diagnostic\xpnetdiag.exe (file missing)
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe
O11 - Options group: [INTERNATIONAL] International*
O16 - DPF: {001EE746-A1F9-460E-80AD-269E088D6A01} (Infotl Control) - http://site.ebrary.com/support/plugins/ebraryRdr.cab
O16 - DPF: {00B71CFB-6864-4346-A978-C0A14556272C} (Checkers Class) - http://messenger.zone.msn.com/binary/msgrchkr.cab31267.cab
O16 - DPF: {4F1E5B1A-2A80-42CA-8532-2D05CB959537} (MSN Photo Upload Tool) - http://labuze64.spaces.live.com//PhotoUpload/MsnPUpld.cab
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://www.update.microsoft.com/...
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) - http://www.update.microsoft.com/...
O16 - DPF: {73F0FD85-BD47-4A95-86D1-DE38860462C1} (PremiumHTML Class) - http://213.254.243.5/data/dialercab/IberoDialerHTML.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
O16 - DPF: {E008A543-CEFB-4559-912F-C27C2B89F13B} (Domino Web Access 7 Control) - https://intranet.k-buy.com/dwa7W.cab
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 - Filter: text/html - {FA6447E7-9383-4913-80B6-E20EEA3B579F} - (no file)
O20 - Winlogon Notify: NavLogon - C:\WINDOWS\System32\NavLogon.dll
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: Apple Mobile Device - Apple, Inc. - C:\Program Files\Fichiers communs\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
O23 - Service: Ati HotKey Poller - Unknown owner - C:\WINDOWS\System32\Ati2evxx.exe
O23 - Service: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Documents and Settings\Administrateur\Bureau\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: EPSON Printer Status Agent2 (EPSONStatusAgent2) - SEIKO EPSON CORPORATION - C:\Program Files\Fichiers communs\EPSON\EBAPI\SAgent2.exe
O23 - Service: IBM PM Service (IBMPMSVC) - Unknown owner - C:\WINDOWS\System32\ibmpmsvc.exe
O23 - Service: Service de l'iPod (iPod Service) - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: Service Framework McAfee (McAfeeFramework) - Network Associates, Inc. - C:\Program Files\Network Associates\Common Framework\FrameworkService.exe
O23 - Service: Network Associates McShield (McShield) - Network Associates, Inc. - C:\Program Files\Network Associates\VirusScan\Mcshield.exe
O23 - Service: Network Associates Task Manager (McTaskManager) - Network Associates, Inc. - C:\Program Files\Network Associates\VirusScan\VsTskMgr.exe
O23 - Service: Intel(R) NMS (NMSSvc) - Intel Corporation - C:\WINDOWS\System32\NMSSvc.exe
O23 - Service: Network Translation Service (NTS) - Unknown owner - C:\WINDOWS\nts.exe
O23 - Service: QCONSVC - Unknown owner - C:\WINDOWS\System32\QCONSVC.EXE

Merci par avance de votre aide!!!

Configuration: Windows XP professionnel
Internet Explorer 7.0