Probleme, mon ordi s'éteind tout seul

Bonjour,
Voila mon problème (et je precise que je n'y connais rien en informatique) mon ordi séteind sans raison (écran bleu se déclanche et l'ordi s'éteind), peut être est ce un virus (sans doute meme) mais je ne sais pas comment faire pour le supprimer.

Merci pour votre aide ;)

Logfile of HijackThis v1.99.1
Scan saved at 17:35:44, on 20/12/2008
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16735)

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\system32\uesiuqcr.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
C:\Program Files\Fichiers communs\LightScribe\LSSrvc.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\RTHDCPL.EXE
C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
C:\Program Files\QuickTime\qttask.exe
C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe
C:\Program Files\MSN Messenger\msnmsgr.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\Program Files\MSN Messenger\livecall.exe
C:\Program Files\WinRAR\WinRAR.exe
C:\DOCUME~1\CATHER~1\LOCALS~1\Temp\Rar$EX00.922\HijackThis.exe

R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://global.acer.com
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Liens
F2 - REG:system.ini: UserInit=C:\WINDOWS\system32\userinit.exe,C:\WINDOWS\system32\uesiuqcr.exe,
O2 - BHO: getwn32.msieof - {DEB3A92B-D7C9-40A7-BB0F-7A408C271C1D} - C:\WINDOWS\system32\getwn32.dll
O3 - Toolbar: (no name) - {4E7BD74F-2B8D-469E-8DA9-FD60BB9AAE33} - (no file)
O4 - HKLM\..\Run: [AzMixerSel] C:\Program Files\Realtek\InstallShield\AzMixerSel.exe
O4 - HKLM\..\Run: [RTHDCPL] RTHDCPL.EXE
O4 - HKLM\..\Run: [SkyTel] SkyTel.EXE
O4 - HKLM\..\Run: [Alcmtr] ALCMTR.EXE
O4 - HKLM\..\Run: [SynTPEnh] C:\Program Files\Synaptics\SynTP\SynTPEnh.exe
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [!AVG Anti-Spyware] "C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\avgas.exe" /minimized
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\msnmsgr.exe" /background
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
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
O11 - Options group: [INTERNATIONAL] International*
O16 - DPF: {6E5E167B-1566-4316-B27F-0DDAB3484CF7} (Image Uploader Control) - http://www.new2.foto.com/ImageUploader4.cab
O16 - DPF: {CE69F98F-2AF3-4306-BAC6-A79070EDA1B4} (Zylom Loader Object) - http://eu.download.games.yahoo.com/zylom/activex/zylomloader.cab
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/flashplayer/current/swflash.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{7859908F-6F29-4581-8607-9EAC051FA587}: NameServer = 80.10.246.2,80.10.246.129
O18 - Protocol: livecall - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - C:\PROGRA~1\MSNMES~1\MSGRAP~1.DLL
O20 - AppInit_DLLs: karna.dat
O20 - Winlogon Notify: puxtydkg - puxtydkg.dll (file missing)
O20 - Winlogon Notify: WgaLogon - C:\WINDOWS\SYSTEM32\WgaLogon.dll
O20 - Winlogon Notify: yayywvs - yayywvs.dll (file missing)
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: Adobe LM Service - Adobe Systems - C:\Program Files\Fichiers communs\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: AVG Anti-Spyware Guard - GRISOFT s.r.o. - C:\Program Files\Grisoft\AVG Anti-Spyware 7.5\guard.exe
O23 - Service: Google Updater Service (gusvc) - Google - C:\Program Files\Google\Common\Google Updater\GoogleUpdaterService.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Fichiers communs\InstallShield\Driver\1150\Intel 32\IDriverT.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Fichiers communs\LightScribe\LSSrvc.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe
O23 - Service: Cycling Manager 2007 Drivers Auto Removal (pr2akt6c) (pr2akt6c) - Cyanide - C:\WINDOWS\system32\pr2akt6c.exe
O23 - Service: Cyberlink RichVideo Service(CRVS) (RichVideo) - Unknown owner - C:\Program Files\CyberLink\Shared Files\RichVideo.exe (file missing)
O23 - Service: TuneUp Drive Defrag Service (TuneUp.Defrag) - TuneUp Software GmbH - C:\WINDOWS\System32\TuneUpDefragService.exe