PC très lent

Bonjour,

Depuis quelques jours, mon PC est très lent.
Merci de me guider.

Je vous mets le rapport de hijackthis :

Logfile of HijackThis v1.99.1
Scan saved at 17:51:23, on 09/11/2007
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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINDOWS\system32\atiptaxx.exe
C:\PROGRA~1\MOUSEW~1\SYSTEM\EM_EXEC.EXE
C:\Apps\ActivBoard\MMKeybd.exe
C:\Program Files\HP\HP Software Update\HPWuSchd2.exe
C:\Program Files\Adobe\Photoshop Album Edition Découverte\3.0\Apps\apdproxy.exe
C:\Program Files\QuickTime\qttask.exe
C:\Program Files\Java\jre1.6.0_01\bin\jusched.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Calendrier\Cld2000.exe
C:\Program Files\HP\Digital Imaging\bin\hpqgalry.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Apps\ActivBoard\nhksrv.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\WINDOWS\system32\slserv.exe
C:\WINDOWS\System32\snmp.exe
C:\WINDOWS\System32\svchost.exe
C:\Apps\ActivBoard\TrayMon.exe
C:\Apps\ActivBoard\OSD.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\sllights.exe
C:\Program Files\Outlook Express\msimn.exe
C:\PROGRA~1\MOZILL~1\FIREFOX.EXE
C:\DOCUME~1\marcel\LOCALS~1\Temp\Répertoire temporaire 1 pour hijackthis.zip\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://portail.free.fr/
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://ww25.planetis.com/
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Window Title = Microsoft Internet Explorer fourni par Planetis
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: (no name) - {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_01\bin\ssv.dll
O4 - HKLM\..\Run: [AtiPTA] atiptaxx.exe
O4 - HKLM\..\Run: [EM_EXEC] C:\PROGRA~1\MOUSEW~1\SYSTEM\EM_EXEC.EXE
O4 - HKLM\..\Run: [ACTIVBOARD] C:\Apps\ActivBoard\MMKeybd.exe
O4 - HKLM\..\Run: [zzzHPSETUP] Q:\Setup.exe \RESET
O4 - HKLM\..\Run: [HP Software Update] "C:\Program Files\HP\HP Software Update\HPWuSchd2.exe"
O4 - HKLM\..\Run: [Adobe Photo Downloader] "C:\Program Files\Adobe\Photoshop Album Edition Découverte\3.0\Apps\apdproxy.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_01\bin\jusched.exe"
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKCU\..\Run: [MoneyAgent] "C:\Program Files\Microsoft Money\System\Money Express.exe"
O4 - HKCU\..\Run: [ccleaner] "C:\Program Files\CCleaner\ccleaner.exe" /AUTO
O4 - HKCU\..\Run: [Cld2000.exe] C:\Program Files\Calendrier\Cld2000.exe
O4 - HKCU\..\Run: [updateMgr] C:\Program Files\Adobe\Acrobat 7.0\Reader\AdobeUpdateManager.exe AcRdB7_0_9
O4 - HKCU\..\Run: [Update Service] "C:\Program Files\Fichiers communs\Teknum Systems\update.exe" /startup
O4 - Global Startup: HP Digital Imaging Monitor.lnk = C:\Program Files\HP\Digital Imaging\bin\hpqtra08.exe
O4 - Global Startup: HP Image Zone Fast Start.lnk = C:\Program Files\HP\Digital Imaging\bin\hpqthb08.exe
O4 - Global Startup: Lancement rapide d'Adobe Reader.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_01\bin\ssv.dll
O9 - Extra button: (no name) - {85d1f590-48f4-11d9-9669-0800200c9a66} - %windir%\bdoscandel.exe (file missing)
O9 - Extra 'Tools' menuitem: Uninstall BitDefender Online Scanner v8 - {85d1f590-48f4-11d9-9669-0800200c9a66} - %windir%\bdoscandel.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
O14 - IERESET.INF: START_PAGE_URL=http://ww25.planetis.com/
O16 - DPF: {5D86DDB5-BDF9-441B-9E9E-D4730F4EE499} (BDSCANONLINE Control) - http://www.bitdefender.fr/scan8/oscan8.cab
O16 - DPF: {BFF1950D-B1B4-4AE8-B842-B2CCF06D9A1B} (Zylom Games Player) - http://game05.zylom.com/activex/zylomgamesplayer.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{8AE11410-66D8-4646-8B79-D6D8A1EFD20C}: NameServer = 213.36.80.1
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O23 - Service: avast! iAVS4 Control Service (aswUpdSv) - ALWIL Software - C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
O23 - Service: Ati HotKey Poller - Unknown owner - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: avast! Antivirus - ALWIL Software - C:\Program Files\Alwil Software\Avast4\ashServ.exe
O23 - Service: avast! Mail Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe" /service (file missing)
O23 - Service: avast! Web Scanner - Unknown owner - C:\Program Files\Alwil Software\Avast4\ashWebSv.exe" /service (file missing)
O23 - Service: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: Netropa NHK Server (nhksrv) - Unknown owner - C:\Apps\ActivBoard\nhksrv.exe
O23 - Service: SmartLinkService (SLService) - - C:\WINDOWS\SYSTEM32\slserv.exe
O23 - Service: SymWMI Service (SymWSC) - Symantec Corporation - C:\Program Files\Fichiers communs\Symantec Shared\Security Center\SymWSC.exe