Keeps turning off

Sounds like a hardware failure. Possilbly the motherboard, more than likely, the power supply.
But then - maybe neither.
Shut it off completely, once you restart, start hitting the F8 key ( once a second ) until you see the " Safe Mode" choices screen. Drop down and select the " Last known Good Configuration" option and hit enter.
If this doesnt work, try the same proceedures ( restart - F8 ) but this time select safe mode - at the top of the list.
If you sucessfully boot in safe mode, you have a system file problem that could be virus related, file table corruptions or registry problems or all combined.

We're here if you need us.
www.wvpcrepair.com

Hey! i had the same problem after i took the computer apart for a clean!!! What happened is that when i took the heatsink off the cpu, the thermal paste had fallen apart a little and i put it back on.... to find computer booting up for about 3 seconds then turning off. i think that when you fire the comp up it turns on the cpu causing it to overheat and shut itself off, just cleaned off old paste and put on some new paste and it fired up! hope this helps you! sorry bout the slight delay!