[Virus] Demande d'assistance

Salut à tous,
Suite à une nouvelle installation de Windows, j'ai du téléchargé quelques utilitaires (anti virus, ventrilo, skype & co). Suite à ces installations, j'ai remarqué que mon pc devenait de plus en plus instable. Des fenêtres publicitaires qui n'arrêtent pas de pop, les logiciels anti-spyware qui bug dès que je lance un scan etc ...

Voici un rappot Hijackthis :

Logfile of Trend Micro HijackThis v2.0.0 (BETA)
Scan saved at 02:35:11, on 06/07/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\TGTSoft\StyleXP\StyleXPService.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\MOM.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Windows Live\Messenger\MsnMsgr.Exe
C:\Program Files\TGTSoft\StyleXP\StyleXP.exe
C:\Program Files\Logitech\MouseWare\system\em_exec.exe
C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\ccc.exe
C:\Program Files\Windows Live\Messenger\usnsvc.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Documents and Settings\Chegirow\Bureau\HiJackThis_v2.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 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: (no name) - {1F6581D5-AA53-4b73-A6F9-41420C6B61F1} - C:\WINDOWS\system32\rcncplqb.dll
O2 - BHO: Skype add-on (mastermind) - {22BF413B-C6D2-4d91-82A9-A0F997BA588C} - C:\Program Files\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
O2 - BHO: (no name) - {53707962-6F74-2D53-2644-206D7942484F} - C:\Program Files\Spybot - Search & Destroy\SDHelper.dll
O2 - BHO: (no name) - {634C7583-74C6-4FEF-BD06-9721761A6815} - C:\WINDOWS\system32\ljjghgh.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: (no name) - {E0A559F3-9189-4C39-8462-2EA103A8C865} - C:\WINDOWS\system32\ssqpn.dll
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [Logitech Utility] Logi_MwX.Exe
O4 - HKLM\..\Run: [StartCCC] C:\Program Files\ATI Technologies\ATI.ACE\Core-Static\CLIStart.exe
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [icq.com] rundll32.exe "C:\WINDOWS\system32\rxkjewjg.dll",forkonce
O4 - HKCU\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\Windows Live\Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [STYLEXP] C:\Program Files\TGTSoft\StyleXP\StyleXP.exe -Hide
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 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\System32\CTFMON.EXE (User 'Default user')
O9 - Extra button: Skype - {77BF5300-1474-4EC7-9980-D32B190E9B07} - C:\Program Files\Skype\Toolbars\Internet Explorer\SkypeIEPlugin.dll
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
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class) - http://www.update.microsoft.com/...
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O18 - Protocol: skype4com - {FFC8B962-9B40-4DFF-9458-1830C7DD7F5D} - C:\PROGRA~1\FICHIE~1\Skype\SKYPE4~1.DLL
O20 - Winlogon Notify: ljjghgh - C:\WINDOWS\SYSTEM32\ljjghgh.dll
O20 - Winlogon Notify: ssqpn - C:\WINDOWS\system32\ssqpn.dll
O22 - SharedTaskScheduler: Pré-chargeur Browseui - {438755C2-A8BA-11D1-B96B-00A0C90312E1} - C:\WINDOWS\System32\browseui.dll
O22 - SharedTaskScheduler: Démon de cache des catégories de composant - {8C7461EF-2B13-11d2-BE35-3078302C2030} - C:\WINDOWS\System32\browseui.dll
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: ATI Smart - Unknown owner - C:\WINDOWS\system32\ati2sgag.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: Service d'administration du Gestionnaire de disque logique (dmadmin) - Unknown owner - C:\WINDOWS\System32\dmadmin.exe
O23 - Service: Journal des événements (Eventlog) - Unknown owner - C:\WINDOWS\system32\services.exe
O23 - Service: Service COM de gravage de CD IMAPI (ImapiService) - Unknown owner - C:\WINDOWS\System32\imapi.exe
O23 - Service: Partage de Bureau à distance NetMeeting (mnmsrvc) - Unknown owner - C:\WINDOWS\System32\mnmsrvc.exe
O23 - Service: Plug-and-Play (PlugPlay) - Unknown owner - C:\WINDOWS\system32\services.exe
O23 - Service: Gestionnaire de session d'aide sur le Bureau à distance (RDSessMgr) - Unknown owner - C:\WINDOWS\system32\sessmgr.exe
O23 - Service: Carte à puce (SCardSvr) - Unknown owner - C:\WINDOWS\System32\SCardSvr.exe
O23 - Service: StyleXPService - Unknown owner - C:\Program Files\TGTSoft\StyleXP\StyleXPService.exe
O23 - Service: Journaux et alertes de performance (SysmonLog) - Unknown owner - C:\WINDOWS\system32\smlogsvc.exe
O23 - Service: Cliché instantané de volume (VSS) - Unknown owner - C:\WINDOWS\System32\vssvc.exe
O23 - Service: Windows Live Setup Service (WLSetupSvc) - Unknown owner - C:\Program Files\Windows Live\installer\WLSetupSvc.exe
O23 - Service: Carte de performance WMI (WmiApSrv) - Unknown owner - C:\WINDOWS\System32\wbem\wmiapsrv.exe
O23 - Service: Service Partage réseau du Lecteur Windows Media (WMPNetworkSvc) - Unknown owner - C:\Program Files\Windows Media Player\WMPNetwk.exe