Portable qui s'éteint....

Bonjour,

J'ai un problème avec mon portable, il s'éteint de temps en temsp sans prévenir, ça peut venir de quoi ?

au cas où je post mon compte rendu Hijack....

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 12:45:17, on 21/11/2007
Platform: Windows 2000 SP4 (WinNT 5.00.2195)
MSIE: Internet Explorer v6.00 SP1 (6.00.2800.1106)
Boot mode: Normal

Running processes:
C:\WINNT\System32\smss.exe
C:\WINNT\system32\winlogon.exe
C:\WINNT\system32\services.exe
C:\WINNT\system32\lsass.exe
C:\WINNT\system32\svchost.exe
C:\WINNT\system32\spoolsv.exe
C:\Program Files\Alwil Software\Avast4\aswUpdSv.exe
C:\WINNT\system32\Ati2evxx.exe
C:\Program Files\Alwil Software\Avast4\ashServ.exe
C:\WINNT\System32\svchost.exe
C:\WINNT\system32\regsvc.exe
C:\WINNT\system32\MSTask.exe
C:\WINNT\System32\WBEM\WinMgmt.exe
C:\WINNT\Explorer.EXE
C:\WINNT\system32\svchost.exe
C:\Program Files\Alwil Software\Avast4\ashWebSv.exe
C:\Program Files\Alwil Software\Avast4\ashMaiSv.exe
C:\WINNT\SOUNDMAN.EXE
C:\WINNT\system32\atiptaxx.exe
C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
C:\WINNT\system32\internat.exe
C:\Program Files\MSN Messenger\MsnMsgr.Exe
C:\Program Files\Belkin\USB F5D7050\Wireless Utility\Belkinwcui.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\Program Files\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page =
https://www.msn.com/fr-fr/
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName
= Liens
O2 - BHO: Aide pour le lien d'Adobe PDF Reader -
{06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Fichiers
communs\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O3 - Toolbar: @msdxmLC.dll,-1@1033,&Radio -
{8E718888-423F-11D2-876E-00A0C9082467} - C:\WINNT\system32\msdxm.ocx
O4 - HKLM\..\Run: [Synchronization Manager] mobsync.exe /logon
O4 - HKLM\..\Run: [SoundMan] SOUNDMAN.EXE
O4 - HKLM\..\Run: [ATIModeChange] Ati2mdxx.exe
O4 - HKLM\..\Run: [AtiPTA] atiptaxx.exe
O4 - HKLM\..\Run: [avast!] C:\PROGRA~1\ALWILS~1\Avast4\ashDisp.exe
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program
Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKCU\..\Run: [internat.exe] internat.exe
O4 - HKCU\..\Run: [MsnMsgr] "C:\Program Files\MSN
Messenger\MsnMsgr.Exe" /background
O4 - HKUS\.DEFAULT\..\Run: [internat.exe] internat.exe (User 'Default
user')
O4 - HKUS\.DEFAULT\..\RunOnce: [^SetupICWDesktop] C:\Program
Files\Internet Explorer\Connection Wizard\icwconn1.exe /desktop (User 'Default
user')
O4 - Global Startup: Belkin Wireless USB Utility.lnk = C:\Program
Files\Belkin\USB F5D7050\Wireless Utility\Belkinwcui.exe
O4 - Global Startup: Microsoft Office.lnk = C:\Program Files\Microsoft
Office\Office\OSA9.EXE
O9 - Extra button: Related - {c95fe080-8f5d-11d2-a20b-00aa003c157a} -
C:\WINNT\web\related.htm
O9 - Extra 'Tools' menuitem: Show &Related Links -
{c95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\WINNT\web\related.htm
O16 - DPF: {6414512B-B978-451D-A0D8-FCFDF33E833C} (WUWebControl Class)
-
http://www.update.microsoft.com/...
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:\WINNT\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: Service d'administration du Gestionnaire de disque
logique (dmadmin) - VERITAS Software Corp. - C:\WINNT\System32\dmadmin.exe
O23 - Service: Sunbelt Personal Firewall 4 (SPF4) - Sunbelt Software -
C:\Program Files\Sunbelt Software\Personal Firewall\kpf4ss.exe