Windows se ferme à heure fixe (12:15)

Bonjour,
Il m'arrive qqch de très bizarre mon windows XP se met à fermer toutes les fenêtres pour finalement s'éteindre tout seul. J'ai installé Windows 7 : même problème au bout de plusieurs jours de fonctionnement....
Voici, un extrait de HiJackThis, si qqun a une idée:
Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 21:23:54, on 25/07/2009
Platform: Unknown Windows (WinNT 6.01.3004)
MSIE: Internet Explorer v8.00 (8.00.7100.0000)
Boot mode: Normal

Running processes:
C:\Windows\system32\taskhost.exe
C:\Windows\system32\Dwm.exe
C:\Windows\Explorer.EXE
C:\Windows\System32\CtHelper.exe
D:\- = = U T I L I T A I R E S = = -\uTorrent\uTorrent.exe
C:\Windows\system32\mmc.exe
D:\- = = I N T E R N E T = = -\Firefox\firefox.exe
I:\DVD_Compilation_3\SOFT ADvanCED OS\ProcessExplorer\procexp.exe
D:\- = = P L A Y E R = = -\Winamp\winamp.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = https://www.bing.com/?toHttps=1&redig=5FC791212101479BAFBE1A679848B1AF
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = https://www.msn.com/fr-fr/?ocid=iehp
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://go.microsoft.com/fwlink/?LinkId=69157
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://www.msn.com/fr-fr/?ocid=iehp
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName =
O4 - HKLM\..\Run: [CTHelper] CTHELPER.EXE
O4 - HKLM\..\Run: [CTxfiHlp] CTXFIHLP.EXE
O4 - HKLM\..\Run: [WinampAgent] "D:\- = = P L A Y E R = = -\Winamp\winampa.exe"
O4 - HKLM\..\Run: [Ad-Watch] C:\Program Files\Lavasoft\Ad-Aware\AAWTray.exe
O4 - HKLM\..\Run: [LogMeIn GUI] "C:\Program Files\LogMeIn\x86\LogMeInSystray.exe"
O4 - HKCU\..\Run: [uTorrent] "D:\- = = U T I L I T A I R E S = = -\uTorrent\uTorrent.exe"
O4 - HKUS\S-1-5-19\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-19\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'LOCAL SERVICE')
O4 - HKUS\S-1-5-20\..\Run: [Sidebar] %ProgramFiles%\Windows Sidebar\Sidebar.exe /autoRun (User 'NETWORK SERVICE')
O4 - HKUS\S-1-5-20\..\RunOnce: [mctadmin] C:\Windows\System32\mctadmin.exe (User 'NETWORK SERVICE')
O4 - HKUS\S-1-5-18\..\Run: [DevconDefaultDB] C:\Windows\system32\READREG /SILENT /FAIL=1 (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [DevconDefaultDB] C:\Windows\system32\READREG /SILENT /FAIL=1 (User 'Default user')
O13 - Gopher Prefix:
O16 - DPF: {D27CDB6E-AE6D-11CF-96B8-444553540000} (Shockwave Flash Object) - http://fpdownload2.macromedia.com/get/shockwave/cabs/flash/swflash.cab
O17 - HKLM\System\CCS\Services\Tcpip\..\{629F7C6F-025A-4A9E-A647-4D2B26251BEF}: NameServer = 212.27.54.252,212.27.53.252
O23 - Service: NVIDIA Display Driver Service (nvsvc) - NVIDIA Corporation - C:\Windows\system32\nvvsvc.exe

--
End of file - 3353 bytes

Pensez-vous que la mise à jour automatique de Windows peut déclencher ce phénomène ??

Sinon, j'ai une info qui pourrait peut être expliqué ce pb dans l observateur d'évenement mais je ne comprends pas la signification :

Log Name: System
Source: Service Control Manager
Date: 25/07/2009 21:01:45
Event ID: 7040
Task Category: None
Level: Information
Keywords: Classic
User: SYSTEM
Computer: mallos-PC
Description:
The start type of the Windows Modules Installer service was changed from auto start to demand start.

Pour finir, un extrait de mes tâches en cours avec ProcessXP:

Process PID CPU Description Company Name User Name Path Command Line Window Status CPU Time Start Time Cycles Delta
System Idle Process 0 93.75 NT AUTHORITY\SYSTEM 1:28:28.105 n/a 4 978 413 309
Interrupts n/a Hardware Interrupts 0:01:36.283 n/a
DPCs n/a Deferred Procedure Calls 0:00:57.455 n/a
System 4 NT AUTHORITY\SYSTEM 0:01:37.875 20:33:41 25/07/2009 74 350 057
smss.exe 260 Windows Session Manager Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\smss.exe \SystemRoot\System32\smss.exe 0:00:00.124 20:33:41 25/07/2009
csrss.exe 384 Client Server Runtime Process Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\csrss.exe %SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows SharedSection=1024,12288,512 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4 ProfileControl=Off MaxRequestThreads=16 0:00:03.104 20:33:54 25/07/2009 96 196
csrss.exe 428 Client Server Runtime Process Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\csrss.exe %SystemRoot%\system32\csrss.exe ObjectDirectory=\Windows SharedSection=1024,12288,512 Windows=On SubSystemType=Windows ServerDll=basesrv,1 ServerDll=winsrv:UserServerDllInitialization,3 ServerDll=winsrv:ConServerDllInitialization,2 ServerDll=sxssrv,4 ProfileControl=Off MaxRequestThreads=16 0:00:11.122 20:33:56 25/07/2009 43 288 653
wininit.exe 436 Windows Start-Up Application Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\wininit.exe wininit.exe 0:00:00.171 20:33:56 25/07/2009
services.exe 476 Services and Controller app Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\services.exe C:\Windows\system32\services.exe 0:00:06.333 20:33:56 25/07/2009 2 327 304
svchost.exe 612 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k DcomLaunch 0:00:02.948 20:33:57 25/07/2009
nvvsvc.exe 668 NVIDIA Driver Helper Service, Version 185.85 NVIDIA Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\nvvsvc.exe C:\Windows\system32\nvvsvc.exe 0:00:00.015 20:33:58 25/07/2009
nvvsvc.exe 1300 NVIDIA Driver Helper Service, Version 185.85 NVIDIA Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\nvvsvc.exe C:\Windows\system32\nvvsvc.exe -session -first 0:00:02.776 20:34:00 25/07/2009 623 415
svchost.exe 696 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\NETWORK SERVICE C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k RPCSS 0:00:00.842 20:33:58 25/07/2009
svchost.exe 744 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe C:\Windows\System32\svchost.exe -k LocalServiceNetworkRestricted 0:00:08.845 20:33:58 25/07/2009
audiodg.exe 3120 Windows Audio Device Graph Isolation Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\audiodg.exe C:\Windows\system32\AUDIODG.EXE 0x2b4 0:00:03.042 20:44:30 25/07/2009 111 533 579
svchost.exe 800 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe C:\Windows\System32\svchost.exe -k LocalSystemNetworkRestricted 0:00:14.055 20:33:58 25/07/2009 174 188
dwm.exe 420 Desktop Window Manager Microsoft Corporation mallos-PC\mallos C:\Windows\System32\dwm.exe "C:\Windows\system32\Dwm.exe" 0:01:13.601 20:34:04 25/07/2009 39 466 634
svchost.exe 840 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k netsvcs 0:00:08.611 20:33:58 25/07/2009 4 359 291
svchost.exe 1068 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k LocalService 0:00:00.764 20:33:59 25/07/2009 259 551
svchost.exe 1180 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\NETWORK SERVICE C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k NetworkService 0:00:02.730 20:33:59 25/07/2009 6 378 195
spoolsv.exe 1456 Spooler SubSystem App Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\spoolsv.exe C:\Windows\System32\spoolsv.exe 0:00:00.093 20:34:01 25/07/2009
svchost.exe 1488 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k LocalServiceNoNetwork 0:00:02.979 20:34:01 25/07/2009
taskhost.exe 304 Host Process for Windows Tasks Microsoft Corporation mallos-PC\mallos C:\Windows\System32\taskhost.exe "taskhost.exe" 0:00:00.405 20:34:04 25/07/2009
SearchIndexer.exe 2872 Microsoft Windows Search Indexer Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\SearchIndexer.exe C:\Windows\system32\SearchIndexer.exe /Embedding 0:00:01.996 20:34:14 25/07/2009 203 790
SearchProtocolHost.exe 2108 Microsoft Windows Search Protocol Host Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\SearchProtocolHost.exe "C:\Windows\system32\SearchProtocolHost.exe" Global\UsGthrFltPipeMssGthrPipe4_ Global\UsGthrCtrlFltPipeMssGthrPipe4 1 -2147483646 "Software\Microsoft\Windows Search" "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT; MS Search 4.0 Robot)" "C:\ProgramData\Microsoft\Search\Data\Temp\usgthrsvc" "DownLevelDaemon" 0:00:00.124 21:30:17 25/07/2009 777 140
SearchFilterHost.exe 1700 Microsoft Windows Search Filter Host Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\SearchFilterHost.exe "C:\Windows\system32\SearchFilterHost.exe" 0 508 512 520 65536 516 0:00:00.062 21:30:17 25/07/2009
svchost.exe 3096 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k LocalServiceAndNoImpersonation 0:00:00.764 20:34:16 25/07/2009 1 371 096
wmpnetwk.exe 3156 Windows Media Player Network Sharing Service Microsoft Corporation NT AUTHORITY\NETWORK SERVICE C:\Program Files\Windows Media Player\wmpnetwk.exe "C:\Program Files\Windows Media Player\wmpnetwk.exe" 0:00:03.213 20:34:16 25/07/2009 463 905
svchost.exe 3296 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\LOCAL SERVICE C:\Windows\System32\svchost.exe C:\Windows\System32\svchost.exe -k LocalServicePeerNet 0:00:04.914 20:34:17 25/07/2009 207 532
svchost.exe 2228 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe C:\Windows\System32\svchost.exe -k secsvcs 0:00:16.052 20:36:11 25/07/2009 24 150
svchost.exe 192 Host Process for Windows Services Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\svchost.exe C:\Windows\system32\svchost.exe -k SDRSVC 0:00:00.031 20:39:05 25/07/2009
lsass.exe 492 Local Security Authority Process Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\lsass.exe C:\Windows\system32\lsass.exe 0:00:04.258 20:33:56 25/07/2009 288 368
lsm.exe 500 Local Session Manager Service Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\lsm.exe C:\Windows\system32\lsm.exe 0:00:00.156 20:33:56 25/07/2009
winlogon.exe 912 Windows Logon Application Microsoft Corporation NT AUTHORITY\SYSTEM C:\Windows\System32\winlogon.exe winlogon.exe 0:00:00.748 20:33:58 25/07/2009
explorer.exe 1092 Windows Explorer Microsoft Corporation mallos-PC\mallos C:\Windows\explorer.exe C:\Windows\Explorer.EXE Running 0:00:49.062 20:34:04 25/07/2009 7 578 163
CtHelper.exe 2252 CtHelper Application Creative Technology Ltd mallos-PC\mallos C:\Windows\System32\CtHelper.exe "C:\Windows\System32\CtHelper.exe" 0:00:00.249 20:34:08 25/07/2009
mmc.exe 2184 Microsoft Management Console Microsoft Corporation mallos-PC\mallos C:\Windows\System32\mmc.exe "C:\Windows\system32\mmc.exe" "C:\Windows\system32\eventvwr.msc" /s Running 0:00:41.433 20:44:52 25/07/2009 118 448
HijackThis.exe 4084 HijackThis Trend Micro Inc. mallos-PC\mallos C:\Program Files\Trend Micro\HijackThis\HijackThis.exe "C:\Program Files\Trend Micro\HijackThis\HijackThis.exe" Running 0:00:05.491 21:23:17 25/07/2009
procexp.exe 3540 4.48 Sysinternals Process Explorer Sysinternals - www.sysinternals.com mallos-PC\mallos I:\DVD_Compilation_3\SOFT ADvanCED OS\ProcessExplorer\procexp.exe "I:\DVD_Compilation_3\SOFT ADvanCED OS\ProcessExplorer\procexp.exe" Running 0:00:05.350 21:30:57 25/07/2009 147 199 751

Merci de votre aide !!!!

Configuration: Windows
Firefox 3.5.1