Computer freezing, shutting down

I've been having problems where my computer freezes, then shuts down by itself, whereupon I have to restart it.

Here is my Hijackthis log, hopefully it's of some help:

Logfile of Trend Micro HijackThis v2.0.2
Scan saved at 6:13:40 PM, on 10/4/2008
Platform: Windows XP SP3 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.6000.16705)
Boot mode: Normal

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:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\Program Files\Lavasoft\Ad-Aware\aawservice.exe
C:\WINDOWS\Explorer.EXE
C:\PROGRA~1\Yahoo!\YOP\yop.exe
C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe
C:\Program Files\ScanSoft\OmniPageSE2.0\OpwareSE2.exe
C:\WINDOWS\ehome\ehtray.exe
C:\Program Files\ATI Technologies\ATI.ACE\cli.exe
C:\Program Files\QuickTime\QTTask.exe
C:\Program Files\Messenger\msmsgs.exe
C:\Program Files\Common Files\Ahead\Lib\NMBgMonitor.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
C:\Program Files\InterVideo\Common\Bin\WinCinemaMgr.exe
C:\PROGRA~1\Yahoo!\browser\ycommon.exe
C:\Program Files\Symantec\LiveUpdate\AluSchedulerSvc.exe
C:\Program Files\Bonjour\mDNSResponder.exe
C:\WINDOWS\eHome\ehRecvr.exe
C:\WINDOWS\eHome\ehSched.exe
C:\Program Files\Common Files\LightScribe\LSSrvc.exe
C:\WINDOWS\system32\svchost.exe
C:\Program Files\Common Files\Symantec Shared\SecurityStatusSDK\SSDK02.exe
C:\WINDOWS\eHome\ehmsas.exe
C:\WINDOWS\system32\dllhost.exe
C:\Program Files\ATI Technologies\ATI.ACE\cli.exe
C:\Program Files\ATI Technologies\ATI.ACE\cli.exe
C:\Program Files\Internet Explorer\iexplore.exe
C:\PROGRA~1\COMMON~1\SYMANT~1\CCPD-LC\symlcsvc.exe
C:\Program Files\Trend Micro\HijackThis\HijackThis.exe

R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://rogers.yahoo.com/
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 = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://go.microsoft.com/fwlink/?LinkId=69157
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://windowsupdate.microsoft.com/
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = *.local
R3 - URLSearchHook: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O2 - BHO: &Yahoo! Toolbar Helper - {02478D38-C3F9-4EFB-9B51-7695ECA05670} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O2 - BHO: Adobe PDF Reader Link Helper - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Common Files\Adobe\Acrobat\ActiveX\AcroIEHelper.dll
O2 - BHO: Yahoo! IE Services Button - {5BAB4B5B-68BC-4B02-94D6-2FC0DE4A7897} - C:\PROGRA~1\Yahoo!\Common\yiesrvc.dll
O2 - BHO: Symantec Intrusion Prevention - {6D53EC84-6AAE-4787-AEEE-F4628F01010C} - C:\PROGRA~1\COMMON~1\SYMANT~1\IDS\IPSBHO.dll
O2 - BHO: SSVHelper Class - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O3 - Toolbar: Easy-WebPrint - {327C2873-E90D-4c37-AA9D-10AC9BABA46C} - C:\Program Files\Canon\Easy-WebPrint\Toolband.dll
O3 - Toolbar: Yahoo! Toolbar - {EF99BD32-C1FB-11D2-892F-0090271D4F88} - C:\Program Files\Yahoo!\Companion\Installs\cpn0\yt.dll
O4 - HKLM\..\Run: [YOP] C:\PROGRA~1\Yahoo!\YOP\yop.exe /autostart
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Program Files\Java\jre1.6.0_07\bin\jusched.exe"
O4 - HKLM\..\Run: [OpwareSE2] "C:\Program Files\ScanSoft\OmniPageSE2.0\OpwareSE2.exe"
O4 - HKLM\..\Run: [NeroFilterCheck] C:\Program Files\Common Files\Ahead\Lib\NeroCheck.exe
O4 - HKLM\..\Run: [IntelAudioStudio] "C:\Program Files\Intel Audio Studio\IntelAudioStudio.exe" TRAY
O4 - HKLM\..\Run: [ehTray] C:\WINDOWS\ehome\ehtray.exe
O4 - HKLM\..\Run: [ATICCC] "C:\Program Files\ATI Technologies\ATI.ACE\cli.exe" runtime -Delay
O4 - HKLM\..\Run: [Adobe Photo Downloader] "C:\Program Files\Adobe\Photoshop Album Starter Edition\3.2\Apps\apdproxy.exe"
O4 - HKLM\..\Run: [Adobe Reader Speed Launcher] "C:\Program Files\Adobe\Reader 8.0\Reader\Reader_sl.exe"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\QTTask.exe" -atboottime
O4 - HKLM\..\Run: [AppleSyncNotifier] C:\Program Files\Common Files\Apple\Mobile Device Support\bin\AppleSyncNotifier.exe
O4 - HKLM\..\Run: [iTunesHelper] "C:\Program Files\iTunes\iTunesHelper.exe"
O4 - HKLM\..\Run: [ccApp] "C:\Program Files\Common Files\Symantec Shared\ccApp.exe"
O4 - HKLM\..\Run: [osCheck] "C:\Program Files\Norton Internet Security\osCheck.exe"
O4 - HKCU\..\Run: [MSMSGS] "C:\Program Files\Messenger\msmsgs.exe" /background
O4 - HKCU\..\Run: [BgMonitor_{79662E04-7C6C-4d9f-84C7-88D8A56B10AA}] "C:\Program Files\Common Files\Ahead\Lib\NMBgMonitor.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKCU\..\Run: [updateMgr] "C:\Program Files\Adobe\Acrobat 7.0\Reader\AdobeUpdateManager.exe" AcRdB7_0_8 -reboot 1
O4 - HKCU\..\Run: [RegistryMechanic] C:\Program Files\Registry Mechanic\RegMech.exe /H
O4 - Global Startup: InterVideo WinCinema Manager.lnk = C:\Program Files\InterVideo\Common\Bin\WinCinemaMgr.exe
O4 - Global Startup: SATARAID5.lnk = ?
O8 - Extra context menu item: Easy-WebPrint Add To Print List - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_AddToList.html
O8 - Extra context menu item: Easy-WebPrint High Speed Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_HSPrint.html
O8 - Extra context menu item: Easy-WebPrint Preview - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Preview.html
O8 - Extra context menu item: Easy-WebPrint Print - res://C:\Program Files\Canon\Easy-WebPrint\Resource.dll/RC_Print.html
O9 - Extra button: (no name) - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O9 - Extra 'Tools' menuitem: Sun Java Console - {08B0E5C0-4FCB-11CF-AAA5-00401C608501} - C:\Program Files\Java\jre1.6.0_07\bin\ssv.dll
O9 - Extra button: Rogers Yahoo! Services - {5BAB4B5B-68BC-4B02-94D6-2FC0DE4A7897} - C:\PROGRA~1\Yahoo!\Common\yiesrvc.dll
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
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
O16 - DPF: {2D8ED06D-3C30-438B-96AE-4D110FDC1FB8} (ActiveScan 2.0 Installer Class) - http://acs.pandasoftware.com/activescan/cabs/as2stubie.cab
O16 - DPF: {30528230-99f7-4bb4-88d8-fa1d4f56a2ab} (Installation Support) - C:\Program Files\Yahoo!\Common\Yinsthelper.dll
O16 - DPF: {644E432F-49D3-41A1-8DD5-E099162EEEC5} (Symantec RuFSI Utility Class) - http://security.symantec.com/sscv6/SharedContent/common/bin/cabsa.cab
O22 - SharedTaskScheduler: {f8d02387-789a-4c0f-a1d8-8a93f33ee4df} - coursings - (no file)
O23 - Service: Lavasoft Ad-Aware Service (aawservice) - Lavasoft - C:\Program Files\Lavasoft\Ad-Aware\aawservice.exe
O23 - Service: Ati HotKey Poller - ATI Technologies Inc. - C:\WINDOWS\system32\Ati2evxx.exe
O23 - Service: ATI Smart - Unknown owner - C:\WINDOWS\system32\ati2sgag.exe
O23 - Service: Automatic LiveUpdate Scheduler - Symantec Corporation - C:\Program Files\Symantec\LiveUpdate\AluSchedulerSvc.exe
O23 - Service: Bonjour Service - Apple Inc. - C:\Program Files\Bonjour\mDNSResponder.exe
O23 - Service: Symantec Event Manager (ccEvtMgr) - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
O23 - Service: Symantec Settings Manager (ccSetMgr) - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
O23 - Service: Symantec Lic NetConnect service (CLTNetCnService) - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
O23 - Service: COM Host (comHost) - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\VAScanner\comHost.exe
O23 - Service: InstallDriver Table Manager (IDriverT) - Macrovision Corporation - C:\Program Files\Common Files\InstallShield\Driver\11\Intel 32\IDriverT.exe
O23 - Service: iPod Service - Apple Inc. - C:\Program Files\iPod\bin\iPodService.exe
O23 - Service: LightScribeService Direct Disc Labeling Service (LightScribeService) - Hewlett-Packard Company - C:\Program Files\Common Files\LightScribe\LSSrvc.exe
O23 - Service: LiveUpdate - Symantec Corporation - C:\Program Files\Symantec\LiveUpdate\LuComServer_3_4.EXE
O23 - Service: LiveUpdate Notice - Symantec Corporation - C:\Program Files\Common Files\Symantec Shared\ccSvcHst.exe
O23 - Service: NBService - Nero AG - C:\Program Files\Nero\Nero 7\Nero BackItUp\NBService.exe
O23 - Service: Symantec Core LC - Unknown owner - C:\PROGRA~1\COMMON~1\SYMANT~1\CCPD-LC\symlcsvc.exe
O23 - Service: YPCService - Yahoo! Inc. - C:\WINDOWS\system32\YPCSER~1.EXE

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End of file - 9437 bytes


Thank you.