computer restarting randomly

every so often my pc reboots itself without warning. the the message appears that the system has recovered from a serious error. I did spybot, CCleaner and Ad-Aware scans, still it reboots itself. Heres the hijackThis log, I wish I could tell whats malicious or not from this, but untill then, ill be posting on AD I guess..

Logfile of HijackThis v1.99.1
Scan saved at 6:42:53 PM, on 19/04/2007
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v6.00 SP2 (6.00.2900.2180)

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\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\cisvc.exe
C:\WINDOWS\eHome\ehRecvr.exe
C:\WINDOWS\eHome\ehSched.exe
C:\WINDOWS\System32\svchost.exe
c:\Program Files\Common Files\LightScribe\LSSrvc.exe
C:\Program Files\Microsoft LifeCam\MSCamSvc.exe
C:\WINDOWS\system32\nvsvc32.exe
C:\WINDOWS\ehome\RMSvc.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\system32\dllhost.exe
C:\WINDOWS\system32\cidaemon.exe
C:\WINDOWS\system32\wscntfy.exe
C:\WINDOWS\Explorer.EXE
C:\WINDOWS\ehome\ehtray.exe
C:\Program Files\MSN Messenger\MsnMsgr.Exe
C:\WINDOWS\eHome\ehmsas.exe
C:\Program Files\Windows Media Player\WMPNSCFG.exe
C:\WINDOWS\ehome\RMSysTry.exe
C:\Program Files\HP\Digital Imaging\bin\hpqtra08.exe
C:\Program Files\MSN Messenger\usnsvc.exe
C:\Program Files\Windows Media Player\wmplayer.exe
C:\Program Files\Mozilla Firefox\firefox.exe
C:\HJT\hijackthis.exe

R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://global.acer.com
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - c:\Program Files\Adobe\Acrobat 7.0\ActiveX\AcroIEHelper.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.5.0_06\bin\ssv.dll
O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O2 - BHO: Windows Live Sign-in Helper - {9030D464-4C02-4ABF-8ECC-5164760863C6} - C:\Program Files\Common Files\Microsoft Shared\Windows Live\WindowsLiveLogin.dll
O4 - HKLM\..\Run: [ehTray] C:\WINDOWS\ehome\ehtray.exe
O4 - HKLM\..\Run: [NvCplDaemon] RUNDLL32.EXE C:\WINDOWS\system32\NvCpl.dll,NvStartup
O4 - HKCU\..\Run: [msnmsgr] "C:\Program Files\MSN Messenger\MsnMsgr.Exe" /background
O4 - HKCU\..\Run: [WMPNSCFG] C:\Program Files\Windows Media Player\WMPNSCFG.exe
O4 - Startup: Adobe Gamma.lnk = C:\Program Files\Common Files\Adobe\Calibration\Adobe Gamma Loader.exe
O4 - Global Startup: Extender Resource Monitor.lnk = C:\WINDOWS\ehome\RMSysTry.exe
O4 - Global Startup: HP Digital Imaging Monitor.lnk = C:\Program Files\HP\Digital Imaging\bin\hpqtra08.exe
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~3\OFFICE11\EXCEL.EXE/3000
O16 - DPF: {00B71CFB-6864-4346-A978-C0A14556272C} (Checkers Class) - http://messenger.zone.msn.com/binary/msgrchkr.cab31267.cab
O16 - DPF: {4F1E5B1A-2A80-42CA-8532-2D05CB959537} (MSN Photo Upload Tool) - http://by107fd.bay107.hotmail.msn.com/resources/MsnPUpld.cab
O16 - DPF: {5D6F45B3-9043-443D-A792-115447494D24} (UnoCtrl Class) - http://messenger.zone.msn.com/EN-CA/a-UNO1/GAME_UNO1.cab
O16 - DPF: {8E0D4DE5-3180-4024-A327-4DFAD1796A8D} (MessengerStatsClient Class) - http://messenger.zone.msn.com/binary/MessengerStatsClient.cab31267.cab
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
O21 - SSODL: WPDShServiceObj - {AAA288BA-9A4C-45B0-95D7-94D524869DB5} - C:\WINDOWS\system32\WPDShServiceObj.dll
O23 - Service: Adobe LM Service - Adobe Systems - C:\Program Files\Common Files\Adobe Systems Shared\Service\Adobelmsvc.exe
O23 - Service: Ares Chatroom server (AresChatServer) - Unknown owner - C:\Program Files\Ares\chatServer.exe (file missing)
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\1150\Intel 32\IDriverT.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - c:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: NVIDIA Display Driver Service (NVSvc) - NVIDIA Corporation - C:\WINDOWS\system32\nvsvc32.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe