computer turning on and off by itself

Ok heres the deal. My computer is turning on and off by itself. I am on XP. When i start it up nothing will load up so i have to use task manager just to open stuff. when i load exploer.exe through task manager it will load like 20 other process that i dont reconigize. then after about 5 minutes it will turn its self off. sometimes sitting in the off postion for about 1 hour the pc will turn its self back on. Is there any possible way to fix it.

 

Have you tried safe mode? Try tapping F8 while the computer is booting, and it should start in safe mode. When booted in safe mode, go to Device Manager and see if it shows any problems with devices.

 

i tried that but the only thing is that it wont let me choose to start up in safe mode nothing will happen so i have to wait like 30 seconds till or what ever the time so it will start. so i am out of ideas right now. Any other sugestions

 

Does your computer ever fully boot windows?

 

no it will boot every thing except exploer.exe i have to do that throught task manager.

 

After you load explorer via Task Manager is your computer usable?

 

A friend of mine downloaded embarq security then deciced he didn't like it so uninstalled it. ever since he did that his PC will start then restart over and over.

I took the battery out for 30 sec.and cleared the cmos, then I could at least get a partial boot or get into safe mode then into system tools where I couldn't find anything wrong?

I can only get one partial boot up using the above, otherwise it will say "Check Sum error" or "Bios rom checksum error" and will start to restart itself again. Mind you it will do this for hours if I let it.

It has no floppy and seems to read the USB Zip disk I hook up to it with the typical boot up from my Win 98se boot up disk downloaded onto the zip, however it completely ignores simple commands like format, fdisk.

It is a Northgate pc (now out of business) with a biostar K8NBP MB, Via VT6307 chip set, Award Bios nForce NPB1015BF, V6.00PG 10/15/03, WD2000BB 120GB HD, AMD ATHLON 64 2800+ processor.
I have the disk that came with the machine but it won't read it, yet it can read a WinXP disk??? :confused

HELP any suggestions as to what to do next besides throw it out the window! :mad