Alerte de virus

Bonjour ,
J'ai deux problèmes depuis deux jours :
1) deux fenêtres apparaissent régulièrement avec comme titre "ULwindowSeek" et "ULwindowUsl" et cela m'embête
2) "le message suivant apparait dans le coin droit en bas de mon ordi : Critical System Eror! System detected virus activities? They may cause critical System failure. Please use antimalware software to clean and protect your système from parasite program. Click here to get all available software"
Et lorsque je click sur la fenêtre la page web de Spyfocon s'affiche me demandant de télécharger le logiciel. Estce que je cours un risque pour mon ordi que faire?? Voici le rapport de hijackthis:
Logfile of HijackThis v1.99.1
Scan saved at 16:26:16, on 16/05/2006
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
D:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
D:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
C:\WINDOWS\system32\HPConfig.exe
D:\Program Files\HPQ\Notebook Utilities\HPWirelessMgr.exe
C:\WINDOWS\system32\inetsrv\inetinfo.exe
C:\Program Files\Fichiers communs\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\WINDOWS\System32\WLTRYSVC.EXE
C:\WINDOWS\System32\bcmwltry.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\explorer.exe
C:\WINDOWS\system32\ctfmon.exe
D:\Program Files\Hijackthis Version Française\VERSION TRADUITE ORIGINALE.EXE

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://us.rd.yahoo.com/customize/i [...] earch.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://us.rd.yahoo.com/customize/i [...] .yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://www.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://us.rd.yahoo.com/customize/i [...] .yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://us.rd.yahoo.com/customize/i [...] earch.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://us.rd.yahoo.com/customize/i [...] .yahoo.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.yahoo.com/
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://us.rd.yahoo.com/customize/i [...] .yahoo.com
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Nothing - {b0398eca-0bcd-4645-8261-5e9dc70248d0} - C:\WINDOWS\system32\hp9CDA.tmp
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - D:\Program Files\Yahoo!\Companion\Installs\cpn1\yt.dll (file missing)
O3 - Toolbar: Adobe PDF - {47833539-D0C5-4125-9FA8-0819E2EAAC93} - D:\Program Files\Adobe\Acrobat 6.0\Acrobat\AcroIEFavClient.dll (file missing)
O3 - Toolbar: Barre d'outils MSN Search - {BDAD1DAD-C946-4A17-ADC1-64B5B4FF55D0} - D:\Program Files\MSN Toolbar Suite\TB\02.05.0000.1105\fr-fr\msntb.dll
O4 - HKLM\..\Run: [CARPService] carpserv.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: [ATIModeChange] Ati2mdxx.exe
O4 - HKLM\..\Run: [ATIPTA] D:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [Cpqset] D:\Program Files\HPQ\Default Settings\cpqset.exe
O4 - HKLM\..\Run: [Display Settings] D:\Program Files\HPQ\Notebook Utilities\hptasks.exe /s
O4 - HKLM\..\Run: [QT4HPOT] D:\Program Files\HPQ\One-Touch\OneTouch.EXE
O4 - HKLM\..\Run: [SunJavaUpdateSched] D:\Program Files\Java\jre1.5.0_06\bin\jusched.exe
O4 - HKLM\..\Run: [MyWinPopupExpress] D:\Program Files\Namtuk\My WinPopup Express\MyWPE.exe
O4 - HKLM\..\Run: [Nty2401] D:\Program Files\Nettoyeur2006\cln.exe stw
O4 - HKLM\..\Run: [17893ae.exe] C:\WINDOWS\system32\17893ae.exe
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [Free Download Manager] D:\Program Files\Free Download Manager\fdm.exe -autorun
O4 - HKCU\..\Run: [MsnMsgr] "D:\Program Files\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [17893ae.exe] C:\Documents and Settings\user\Local Settings\Application Data\17893ae.exe
O4 - Startup: .protected
O4 - Startup: Lancement rapide de Microsoft Office OneNote 2003.lnk = D:\Program Files\Microsoft Office\OFFICE11\ONENOTEM.EXE
O4 - Global Startup: .protected
O4 - Global Startup: Assistant d'Acrobat.lnk = D:\Program Files\Adobe\Acrobat 6.0\Distillr\acrotray.exe
O4 - Global Startup: Lancement rapide de Microsoft Office OneNote 2003.lnk = D:\Program Files\Microsoft Office\OFFICE11\ONENOTEM.EXE
O4 - Global Startup: Windows Desktop Search.lnk = D:\Program Files\MSN Toolbar Suite\DS\02.05.0001.1119\fr-fr\bin\WindowsSearch.exe
O8 - Extra context menu item: &MSN Search - res://D:\Program Files\MSN Toolbar Suite\TB\02.05.0000.1105\fr-fr\msntb.dll/search.htm
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://D:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O8 - Extra context menu item: Ouvrir dans un nouvel onglet d'arrière-plan - res://D:\Program Files\MSN Toolbar Suite\TAB\02.05.0000.1105\fr-fr\msntabres.dll/229?8b86a587694440f9b4b547dc52c839f
O8 - Extra context menu item: Ouvrir dans un nouvel onglet de premier plan - res://D:\Program Files\MSN Toolbar Suite\TAB\02.05.0000.1105\fr-fr\msntabres.dll/230?8b86a587694440f9b4b547dc52c839f
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - D:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - D:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O9 - Extra button: Run WinHTTrack - {36ECAF82-3300-8F84-092E-AFF36D6C7040} - D:\Program Files\WinHTTrack\WinHTTrackIEBar.dll
O9 - Extra 'Tools' menuitem: Launch WinHTTrack - {36ECAF82-3300-8F84-092E-AFF36D6C7040} - D:\Program Files\WinHTTrack\WinHTTrackIEBar.dll
O9 - Extra button: Messenger - {4528BBE0-4E08-11D5-AD55-00010333D0AD} - D:\PROGRA~1\Yahoo!\Common\yhexbmesfr.dll
O9 - Extra 'Tools' menuitem: Yahoo! Messenger - {4528BBE0-4E08-11D5-AD55-00010333D0AD} - D:\PROGRA~1\Yahoo!\Common\yhexbmesfr.dll
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - D:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - D:\Program Files\Messenger\msmsgs.exe
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - D:\Program Files\Messenger\msmsgs.exe
O16 - DPF: {17492023-C23A-453E-A040-C7C580BBF700} (Windows Genuine Advantage Validation Tool) - http://go.microsoft.com/fwlink/?linkid=39204
O16 - DPF: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (YInstStarter Class) - D:\Program Files\Yahoo!\Common\yinsthelper.dll
O16 - DPF: {6E32070A-766D-4EE6-879C-DC1FA91D2FC3} (MUWebControl Class) - http://update.microsoft.com/micros [...] 3354986672
O16 - DPF: {74CD40EA-EF77-4BAD-808A-B5982DA73F20} - http://yax-download.yazzle.net/Yaz [...] refid=1123
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "D:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
O20 - Winlogon Notify: wingzn32 - C:\WINDOWS\SYSTEM32\wingzn32.dll
O23 - Service: AVG7 Alert Manager Server (Avg7Alrt) - GRISOFT, s.r.o. - D:\PROGRA~1\Grisoft\AVGFRE~1\avgamsvr.exe
O23 - Service: AVG7 Update Service (Avg7UpdSvc) - GRISOFT, s.r.o. - D:\PROGRA~1\Grisoft\AVGFRE~1\avgupsvc.exe
O23 - Service: HP Configuration Interface Service (HPConfig) - Hewlett-Packard - C:\WINDOWS\system32\HPConfig.exe
O23 - Service: HPWirelessMgr - Hewlett-Packard Co. - D:\Program Files\HPQ\Notebook Utilities\HPWirelessMgr.exe
O23 - Service: WLTRYSVC - Unknown owner - C:\WINDOWS\System32\WLTRYSVC.EXE