Pics d'utilisation d'unité centrale

Help!
Depuis quelque temps, mon ordi met énormement de temps au démarrage, puis, entraîne des pics d'utilisation de mon uc à minimum 80% dès que j'ouvre une page internet ou un programme. J'ai beau eu faire scan, défragmentation, virer les programmes inutiles du démarrage, .. rien n'y fait!
Si quelqu'un a une idée ou veut bien prendre le temps de m'aider je le remercie d'avance! :)

Je poste mon log si quelqu'un y trouve quelque chose :

Logfile of random's system information tool 1.06 (written by random/random)
Run by Nicolas at 2010-04-13 20:40:56
Microsoft Windows XP Professionnel Service Pack 3
System drive C: has 31 GB (21%) free of 150 GB
Total RAM: 1023 MB (68% free)

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 20:41:23, on 13/04/2010
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v8.00 (8.00.6001.18702)
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:\Program Files\Windows Defender\MsMpEng.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:\Program Files\Bonjour\mDNSResponder.exe
C:\Program Files\Java\jre6\bin\jqs.exe
C:\Program Files\Fichiers communs\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Program Files\Canon\MultiPASS4\MPSERVIC.EXE
C:\WINDOWS\system32\svchost.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
C:\Program Files\Windows Defender\MSASCui.exe
C:\Program Files\Fichiers communs\Java\Java Update\jusched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Fichiers communs\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
C:\Documents and Settings\Nicolas\Bureau\Nicolas\Load\RSIT\RSIT.exe
C:\Program Files\trend micro\Nicolas.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://www.google.fr/toolbar/ie8/sidebar.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = https://www.google.fr/?gws_rd=ssl
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 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://www.google.fr/toolbar/ie8/sidebar.html
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://www.google.fr/keyword/%s
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - Default URLSearchHook is missing
O2 - BHO: (no name) - {243B17DE-77C7-46BF-B94B-0B5F309A0E64} - C:\Program Files\Microsoft Money\System\mnyside.dll
O2 - BHO: (no name) - {5C255C8A-E604-49b4-9D64-90988571CECB} - (no file)
O2 - BHO: Programme d'aide de l'Assistant de connexion Windows Live - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Fichiers communs\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Program Files\Java\jre6\bin\jp2ssv.dll
O2 - BHO: JQSIEStartDetectorImpl - {E7E6F031-17CE-4C07-BC86-EABFE594F69C} - C:\Program Files\Java\jre6\lib\deploy\jqs\ie\jqs_plugin.dll
O2 - BHO: (no name) - {FDD3B846-8D59-4ffb-8758-209B6AD74ACC} - (no file)
O4 - HKLM\..\Run: [AlcxMonitor] ALCXMNTR.EXE
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [Windows Defender] "C:\Program Files\Windows Defender\MSASCui.exe" -hide
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Fichiers communs\Java\Java Update\jusched.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKUS\S-1-5-19\..\RunOnce: [Config] %systemroot%\system32\run.cmd (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\RunOnce: [nlsf] cmd.exe /C move /Y "%SystemRoot%\System32\syssetub.dll" "%SystemRoot%\System32\syssetup.dll" (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-19\..\RunOnce: [tscuninstall] %systemroot%\system32\tscupgrd.exe (User 'SERVICE LOCAL')
O4 - HKUS\S-1-5-20\..\RunOnce: [Config] %systemroot%\system32\run.cmd (User 'SERVICE RÉSEAU')
O4 - HKUS\S-1-5-18\..\RunOnce: [Config] %systemroot%\system32\run.cmd (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\RunOnce: [Config] %systemroot%\system32\run.cmd (User 'Default user')
O8 - Extra context menu item: Add to Google Photos Screensa&ver - res://C:\WINDOWS\system32\GPhotos.scr/200
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: MoneySide - {E023F504-0C5A-4750-A1E7-A9046DEA8A21} - C:\Program Files\Microsoft Money\System\mnyside.dll
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
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://update.microsoft.com/...
O23 - Service: Apple Mobile Device - Apple Inc. - C:\Program Files\Fichiers communs\Apple\Mobile Device Support\bin\AppleMobileDeviceService.exe
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 Bonjour (Bonjour Service) - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: FLEXnet Licensing Service - Acresso Software Inc. - C:\Program Files\Fichiers communs\Macrovision Shared\FLEXnet Publisher\FNPLicensingService.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Sun Microsystems, Inc. - C:\Program Files\Java\jre6\bin\jqs.exe
O23 - Service: MpService - Canon Inc. - C:\Program Files\Canon\MultiPASS4\MPSERVIC.EXE