Problem with system shutting down

My system sometimes shuts down as if my power cord was unplugged, very quick. The power LEDs, mouse, etc all stay lit though. Someone said it was a virus so here's my log... please help

Logfile of HijackThis v1.99.1
Scan saved at 6:18:28 PM, on 8/13/2005
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\Ati2evxx.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\spoolsv.exe
C:\Program Files\Executive Software\Diskeeper\DkService.exe
C:\WINDOWS\system32\RioMSC.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\system32\Ati2evxx.exe
C:\WINDOWS\system32\devldr32.exe
C:\WINDOWS\Explorer.EXE
C:\Program Files\Mozilla Firefox\firefox.exe
C:\WINDOWS\system32\rundll32.exe
C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
C:\WINDOWS\System32\spool\DRIVERS\W32X86\3\E_S0BIC1.EXE
C:\Program Files\D-Tools\daemon.exe
C:\Program Files\Common Files\Microsoft Shared\Source Engine\OSE.EXE
D:\Download\HijackThis.exe

R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyServer = 219.148.151.179:8080
O1 - Hosts: 202.157.177.11 bitconsole.com www.bitconsole.com
O1 - Hosts: 202.157.177.11 unique#.tracker.bitconsole.com
O2 - BHO: AcroIEHlprObj Class - {06849E9F-C8D7-4D59-B87D-784B7D6BE0B3} - C:\Program Files\Adobe\Acrobat 6.0\Reader\ActiveX\AcroIEHelper.dll
O2 - BHO: FlashFXP Helper for Internet Explorer - {E5A1691B-D188-4419-AD02-90002030B8EE} - C:\PROGRA~1\FlashFXP\IEFlash.dll
O4 - HKLM\..\Run: [BluetoothAuthenticationAgent] rundll32.exe bthprops.cpl,,BluetoothAuthenticationAgent
O4 - HKLM\..\Run: [UpdReg] C:\WINDOWS\Updreg.exe
O4 - HKLM\..\Run: [ATIPTA] C:\Program Files\ATI Technologies\ATI Control Panel\atiptaxx.exe
O4 - HKLM\..\Run: [EPSON Stylus C62 Series] C:\WINDOWS\System32\spool\DRIVERS\W32X86\3\E_S0BIC1.EXE /P23 "EPSON Stylus C62 Series" /O6 "USB001" /M "Stylus C62"
O4 - HKLM\..\Run: [QuickTime Task] "C:\Program Files\QuickTime\qttask.exe" -atboottime
O4 - HKLM\..\Run: [DiskeeperSystray] "C:\Program Files\Executive Software\Diskeeper\DkIcon.exe"
O4 - HKLM\..\Run: [DAEMON Tools-1033] "C:\Program Files\D-Tools\daemon.exe" -lang 1033
O4 - HKCU\..\Run: [NBJ] "C:\Program Files\Ahead\Nero BackItUp\NBJ.exe"
O4 - Global Startup: Microsoft Office.lnk = C:\Program Files\Microsoft Office\Office10\OSA.EXE
O8 - Extra context menu item: E&xport to Microsoft Excel - res://C:\PROGRA~1\MICROS~2\OFFICE11\EXCEL.EXE/3000
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~2\OFFICE11\REFIEBAR.DLL
O9 - Extra button: AIM - {AC9E2541-2814-11d5-BC6D-00B0D0A1DE45} - C:\Program Files\AIM\aim.exe
O9 - Extra button: PartyPoker.com - {B7FE5D70-9AA2-40F1-9C6B-12A255F085E1} - C:\Program Files\PartyPoker\PartyPoker.exe (file missing)
O9 - Extra 'Tools' menuitem: PartyPoker.com - {B7FE5D70-9AA2-40F1-9C6B-12A255F085E1} - C:\Program Files\PartyPoker\PartyPoker.exe (file missing)
O9 - Extra button: Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe (file missing)
O9 - Extra 'Tools' menuitem: Windows Messenger - {FB5F1910-F110-11d2-BB9E-00C04F795683} - C:\Program Files\Messenger\msmsgs.exe (file missing)
O23 - Service: Adobe LM Service - Unknown owner - C:\Program Files\Common Files\Adobe Systems Shared\Service\Adobelmsvc.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: Diskeeper - Executive Software International, Inc. - C:\Program Files\Executive Software\Diskeeper\DkService.exe
O23 - Service: Rio MSC Manager (RioMSC) - Digital Networks North America, Inc. - C:\WINDOWS\system32\RioMSC.exe