Urgent!!! Mon ordinateur est super lent

Bonjour,
mon ordinteur depuis quelque jour et super lent je me demande bien pourquoi d'ailleur.
En plus j'ai le projet a rendre cette semaine, j'aimerais donc que quel qu'un m'aide a resoudre le pb de ralentissement de mon ordi

Je vous donne l'analyse faite avec HijackThis:
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 20:41:43, on 18/12/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16574)
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:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\System32\wltrysvc.exe
C:\WINDOWS\System32\bcmwltry.exe
C:\Program Files\Lavasoft\Ad-Aware 2007\aawservice.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
C:\WINDOWS\SOUNDMAN.EXE
C:\WINDOWS\system32\WLTRAY.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\Program Files\Eset\nod32kui.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
C:\Program Files\Google\GoogleToolbarNotifier\1.2.1128.5462\GoogleToolbarNotifier.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\WINDOWS\system32\E_S00RP1.EXE
C:\Program Files\Fichiers communs\Microsoft Shared\VS7DEBUG\MDM.EXE
C:\Program Files\Nero\Nero8\Nero BackItUp\NBService.exe
C:\Program Files\Eset\nod32krn.exe
C:\Program Files\SolidDocuments\SolidConverterPDF\SCPDF\SolidPdfService.exe
C:\WINDOWS\system32\svchost.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.google.fr
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
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
O2 - BHO: Solid Converter PDF - {259F616C-A300-44F5-B04A-ED001A26C85C} - C:\Program Files\SolidDocuments\SolidConverterPDF\SCPDF\ExploreExtPDF.dll
O2 - BHO: Spybot-S&D IE Protection - {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_03\bin\ssv.dll
O2 - BHO: Google Toolbar Helper - {AA58ED58-01DD-4d91-8333-CF10577473F7} - c:\program files\google\googletoolbar2.dll
O3 - Toolbar: Solid Converter PDF - {259F616C-A300-44F5-B04A-ED001A26C85C} - C:\Program Files\SolidDocuments\SolidConverterPDF\SCPDF\ExploreExtPDF.dll
O3 - Toolbar: &Google - {2318C2B1-4965-11d4-9B18-009027A5CD4F} - c:\program files\google\googletoolbar2.dll
O4 - HKLM\..\Run: [IMJPMIG8.1] "C:\WINDOWS\IME\imjp8_1\IMJPMIG.EXE" /Spoil /RemAdvDef /Migration32
O4 - HKLM\..\Run: [MSPY2002] C:\WINDOWS\system32\IME\PINTLGNT\ImScInst.exe /SYNC
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [Broadcom Wireless Manager UI] C:\WINDOWS\system32\WLTRAY
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [nod32kui] "C:\Program Files\Eset\nod32kui.exe" /WAITSERVICE
O4 - HKLM\..\Run: [Microsoft Works Update Detection] C:\Program Files\Fichiers communs\Microsoft Shared\Works Shared\WkUFind.exe
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [SpybotSD TeaTimer] C:\Program Files\Spybot - Search & Destroy\TeaTimer.exe
O4 - HKCU\..\Run: [swg] C:\Program Files\Google\GoogleToolbarNotifier\1.2.1128.5462\GoogleToolbarNotifier.exe
O8 - Extra context menu item: E&xporter vers Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Console Java (Sun) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_03\bin\ssv.dll
O9 - Extra button: Recherche - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: (no name) - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
O9 - Extra 'Tools' menuitem: Spybot - Search & Destroy Configuration - {DFB852A3-47F8-48C4-A200-58CAB36FD2A2} - C:\PROGRA~1\SPYBOT~1\SDHelper.dll
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
O9 - Extra button: (no name) - SolidConverterPDF - (no file) (HKCU)
O14 - IERESET.INF: START_PAGE_URL=http://www.files-ftp.com/~unicorni/phpBB2/index.php
O23 - Service: Ad-Aware 2007 Service (aawservice) - Lavasoft AB - C:\Program Files\Lavasoft\Ad-Aware 2007\aawservice.exe
O23 - Service: Adobe LM Service - Adobe Systems - C:\Program Files\Fichiers communs\Adobe Systems Shared\Service\Adobelmsvc.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: 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: ##Id_String1.6844F930_1628_4223_B5CC_5BB94B879762## (Bonjour Service) - Apple Computer, Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: EPSON V3 Service2(03) (EPSON_PM_RPCV2_01) - SEIKO EPSON CORPORATION - C:\WINDOWS\system32\E_S00RP1.EXE
O23 - Service: FLEXnet Licensing Service - Macrovision Europe Ltd. - 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: Nero BackItUp Scheduler 3 - Nero AG - C:\Program Files\Nero\Nero8\Nero BackItUp\NBService.exe
O23 - Service: NMIndexingService - Nero AG - C:\Program Files\Fichiers communs\Nero\Lib\NMIndexingService.exe
O23 - Service: NOD32 Kernel Service (NOD32krn) - Eset - C:\Program Files\Eset\nod32krn.exe
O23 - Service: SolidPDFConverterReadSpool (ScReadSpool) - VoyagerSoft, LLC - C:\Program Files\SolidDocuments\SolidConverterPDF\SCPDF\SolidPdfService.exe
O23 - Service: Broadcom Wireless LAN Tray Service (wltrysvc) - Unknown owner - C:\WINDOWS\System32\wltrysvc.exe