Trés gros ralentissement!

Bonjour,

j'ai acquéri un pc Acer il y a un mois.J'avais la version de norton en démo(comme beaucoup de pc neuf :( ).Depuis quelques temps, j'ai de gros ralentissements.J'ai viré norton et installé Antivir gratuit mais impossible de faire des mises à jour et les problèmes de lenteur sont restés.
En bref, j'aimerais que vous m'aidiez à résoudre ces problèmes,
merci.

P.S: voici mon rapport Hijack:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 19:19:19, on 01/11/2007
Platform: Windows Vista (WinNT 6.00.1904)
MSIE: Internet Explorer v7.00 (7.00.6000.16546)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskeng.exe
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Program Files\Windows Defender\MSASCui.exe
C:\Windows\RtHDVCpl.exe
C:\Windows\System32\SysMonitor.exe
C:\Acer\Empowering Technology\eDataSecurity\eDSloader.exe
C:\Acer\Empowering Technology\eMode\PCM\PCMService.exe
C:\Program Files\AntiVir PersonalEdition Classic\avgnt.exe
C:\Acer\Empowering Technology\ACER.EMPOWERING.FRAMEWORK.SUPERVISOR.EXE
C:\Acer\Empowering Technology\eRecovery\ERAGENT.EXE
C:\Program Files\Internet Explorer\ieuser.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Windows\system32\Macromed\Flash\FlashUtil9b.exe
C:\Users\le pite\TEST.exe
C:\Users\le pite\Documents\Test.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://fr.rd.yahoo.com/customize/ycomp/defaults/sp/*https://fr.yahoo.com/
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 = http://fr.fr.acer.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://go.microsoft.com/fwlink/?LinkId=54896
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://fr.yahoo.com/
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://fr.rd.yahoo.com/customize/ycomp/defaults/su/*https://fr.yahoo.com/
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
R3 - URLSearchHook: Yahoo! Toolbar avec bloqueur de fenêtres pop-up - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O1 - Hosts: ::1 localhost
O2 - BHO: Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O2 - BHO: AcroIEHlprObj Class - {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: ShowBarObj Class - {83A2F9B1-01A2-4AA5-87D1-45B6B8505E96} - C:\Windows\system32\ActiveToolBand.dll
O3 - Toolbar: Yahoo! Toolbar avec bloqueur de fenêtres pop-up - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn\yt.dll
O3 - Toolbar: Acer eDataSecurity Management - {5CBE3B7C-1E47-477e-A7DD-396DB0476E29} - C:\Windows\system32\eDStoolbar.dll
O4 - HKLM\..\Run: [Windows Defender] %ProgramFiles%\Windows Defender\MSASCui.exe -hide
O4 - HKLM\..\Run: [RtHDVCpl] RtHDVCpl.exe
O4 - HKLM\..\Run: [Acer Empowering Technology Monitor] C:\Windows\system32\SysMonitor.exe
O4 - HKLM\..\Run: [WarReg_PopUp] C:\Acer\WR_PopUp\WarReg_PopUp.exe
O4 - HKLM\..\Run: [eDataSecurity Loader] C:\Acer\Empowering Technology\eDataSecurity\eDSloader.exe
O4 - HKLM\..\Run: [PCMService] "C:\Acer\Empowering Technology\eMode\PCM\PCMService.exe"
O4 - HKLM\..\Run: [avgnt] "C:\Program Files\AntiVir PersonalEdition Classic\avgnt.exe" /min
O4 - HKCU\..\Run: [?????????] ??????????????e
O4 - Global Startup: Adobe Reader Speed Launch.lnk = C:\Program Files\Adobe\Acrobat 7.0\Reader\reader_sl.exe
O4 - Global Startup: Empowering Technology Launcher.lnk = ?
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
O13 - Gopher Prefix:
O23 - Service: Ad-Aware 2007 Service (aawservice) - Lavasoft AB - C:\Program Files\Lavasoft\Ad-Aware 2007\aawservice.exe
O23 - Service: ePerformance Service (AcerMemUsageCheckService) - Unknown owner - C:\Acer\Empowering Technology\ePerformance\MemCheck.exe
O23 - Service: AntiVir PersonalEdition Classic Scheduler (AntiVirScheduler) - Avira GmbH - C:\Program Files\AntiVir PersonalEdition Classic\sched.exe
O23 - Service: AntiVir PersonalEdition Classic Guard (AntiVirService) - Avira GmbH - C:\Program Files\AntiVir PersonalEdition Classic\avguard.exe
O23 - Service: CyberLink Background Capture Service (CBCS) (CLCapSvc) - Unknown owner - C:\Acer\Empowering Technology\eMode\PCM\Kernel\TV\CLCapSvc.exe
O23 - Service: CyberLink Task Scheduler (CTS) (CLSched) - Unknown owner - C:\Acer\Empowering Technology\eMode\PCM\Kernel\TV\CLSched.exe
O23 - Service: eRecovery Service (eRecoveryService) - Acer Inc. - C:\Acer\Empowering Technology\eRecovery\eRecoveryService.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe
O23 - Service: Symantec Core LC - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\CCPD-LC\symlcsvc.exe