Win32:Obfuscated-BPS et window installer

Bonjour,
Mon ordinateur a plusieurs problèmes, le premier est que je toutes les installations ou desinstalations passant par window installer sont impossibles et le second est celui ci, je recois des alertes de mon antivirus a chaque début de session : Win32:Obfuscated-BPS et il me dit que je suis infecté, quand je veux le supprimer cela ne fonctionne pas, je vous post le rapport de hijack this :
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 20:34:15, on 28/10/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)
Boot mode: Normal

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:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Documents and Settings\gajecki\Mes documents\eDonkey2000 Downloads\AVG Anti-Spyware 7.5\guard.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe
C:\WINDOWS\VM_STI.EXE
C:\Documents and Settings\gajecki\Mes documents\eDonkey2000 Downloads\AVG Anti-Spyware 7.5\avgas.exe
C:\PROGRA~1\Wanadoo\TaskBarIcon.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\PROGRA~1\Wanadoo\GestionnaireInternet.exe
C:\PROGRA~1\Wanadoo\ComComp.exe
C:\WINDOWS\system32\wuauclt.exe
C:\PROGRA~1\Wanadoo\Toaster.exe
C:\PROGRA~1\Wanadoo\Inactivity.exe
C:\PROGRA~1\Wanadoo\PollingModule.exe
C:\WINDOWS\System32\ALERTM~1\ALERTM~1.EXE
C:\PROGRA~1\Wanadoo\Watch.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\WinRAR\WinRAR.exe
C:\Documents and Settings\gajecki\Bureau\BlaBla\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = https://www.bing.com/?cc=fr&toHttps=1&redig=D4322FEE7CF74A348CB9CE970F098EF5
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://fr.rd.yahoo.com/customize/ie/defaults/sp/msgr8/*https://fr.search.yahoo.com/
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://fr.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://fr.rd.yahoo.com/customize/ie/defaults/su/msgr8/*https://fr.search.yahoo.com/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://fr.rd.yahoo.com/customize/ie/defaults/sp/msgr8/*https://fr.search.yahoo.com/
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://fr.rd.yahoo.com/customize/ie/defaults/su/msgr8/*https://fr.search.yahoo.com/
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page =
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Orange
R3 - URLSearchHook: i-Nav IDN SearchHook - {CE000994-A58C-4441-8938-744CD72AB27F} - C:\Program Files\VeriSign\i-Nav\i-nav_4_2_1.dll
R3 - URLSearchHook: Search Class - {08C06D61-F1F3-4799-86F8-BE1A89362C85} - C:\PROGRA~1\Wanadoo\SEARCH~1.DLL
R3 - URLSearchHook: (no name) - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - (no file)
O2 - BHO: (no name) - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - (no file)
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O2 - BHO: i-Nav IDN Resolver - {CE000992-A58C-4441-8938-744CD72AB27F} - C:\Program Files\VeriSign\i-Nav\i-nav_4_2_1.dll
O3 - Toolbar: (no name) - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - (no file)
O4 - HKLM\..\Run: [TkBellExe] "C:\Program Files\Fichiers communs\Real\Update_OB\realsched.exe" -osboot
O4 - HKLM\..\Run: [BigDogPath] C:\WINDOWS\VM_STI.EXE Audio Web Cam 31
O4 - HKLM\..\Run: [WOOWATCH] C:\PROGRA~1\Wanadoo\Watch.exe
O4 - HKLM\..\Run: [WOOTASKBARICON] C:\PROGRA~1\Wanadoo\GestMaj.exe TaskBarIcon.exe
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Documents and Settings\gajecki\Mes documents\eDonkey2000 Downloads\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [Bird Burn] C:\DOCUME~1\gajecki\APPLIC~1\ISOSTO~1\FirstTwoCurb.exe
O4 - HKCU\..\Run: [WOOKIT] C:\Program Files\Wanadoo\Shell.exe appLaunchClientZone.shl|PARAM= cnx
O4 - HKLM\..\Policies\Explorer\Run: [user32.dll] C:\Program Files\Video ActiveX Access\iesmn.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SERVICE RÉSEAU')
O4 - Global Startup: Omega Messenger.lnk = C:\Program Files\Omega Informatix\Omega Messenger\Omega Messenger.exe
O9 - Extra button: Europa Casino - {4C826F10-D34B-4ba8-B609-1FB8C6482A05} - C:\Casino\Europa Casino\casino.exe
O9 - Extra 'Tools' menuitem: Europa Casino - {4C826F10-D34B-4ba8-B609-1FB8C6482A05} - C:\Casino\Europa Casino\casino.exe
O9 - Extra button: Aide i-Nav - {CE000992-A58C-4441-8938-744CD72AB27F} - http://idn.verisign-grs.com/plug-in/support/index.jsp (file missing)
O9 - Extra 'Tools' menuitem: Aide i-Nav - {CE000992-A58C-4441-8938-744CD72AB27F} - http://idn.verisign-grs.com/plug-in/support/index.jsp (file missing)
O9 - Extra button: (no name) - {CE000996-A58C-4441-8938-744CD72AB27F} - C:\Program Files\VeriSign\i-Nav\i-nav_4_2_1.dll
O9 - Extra 'Tools' menuitem: Options i-Nav - {CE000996-A58C-4441-8938-744CD72AB27F} - C:\Program Files\VeriSign\i-Nav\i-nav_4_2_1.dll
O9 - Extra button: Messager Wanadoo - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\PROGRA~1\MESSAG~1\Messager Wanadoo.exe
O9 - Extra 'Tools' menuitem: Messager Wanadoo - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\PROGRA~1\MESSAG~1\Messager Wanadoo.exe
O9 - Extra button: Orange - {1462651F-F4BA-4C76-A001-C4284D0FE16E} - https://www.orange.fr/portail (file missing) (HKCU)
O10 - Unknown file in Winsock LSP: c:\windows\system32\nwprovau.dll
O16 - DPF: Yahoo! Pool 2 - http://download2.games.yahoo.com/games/clients/y/poti_x.cab
O16 - DPF: {16BED5D9-AA6B-4A96-A134-C1958893490F} - http://advnt01.com/dialer/intES_ver40v.CAB
O16 - DPF: {2B323CD9-50E3-11D3-9466-00A0C9700498} - http://download.games.yahoo.com/games/voice/yacscom.cab
O16 - DPF: {AB86CE53-AC9F-449F-9399-D8ABCA09EC09} (Get_ActiveX Control) - https://h17000.www1.hp.com/ewfrf-JAVA/Secure/HPGetDownloadManager.ocx
O16 - DPF: {D0C0F75C-683A-4390-A791-1ACFD5599AB8} (Oberon Flash Game Host) - http://jeuxmultijoueurs.orange.fr/Gameshell/GameHost/1.0/OberonGameHost.cab
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:\Documents and Settings\gajecki\Mes documents\eDonkey2000 Downloads\AVG Anti-Spyware 7.5\guard.exe
O24 - Desktop Component 0: (no name) - http://yahooo.jexiste.fr/images/avatars/68355246743c9135156847.png
O24 - Desktop Component 1: (no name) - http://ouafik08.skyblog.com/pics/383621624_small.jpg
O24 - Desktop Component 2: (no name) - http://ouafik08.skyblog.com/pics/384765607.gif
O24 - Desktop Component 3: (no name) - http://ouafik08.skyblog.com/pics/384768377.gif
O24 - Desktop Component 4: (no name) - http://www.fdr-skatepark.com/FDRBANNER2.gif
O24 - Desktop Component 6: Security info v3 - C:\WINDOWS\screen.html

Merci d'avance à ceux qui peuvent m'aider