But given the clues we can't offer much. Any added information such as if the CPU heatsink is still on, if you have added a 3D video card could help in diagnosis.
as soon as i turn my pc on it just shuts off in 2 seconds.
i don't even get a signal on my monitor. i have already replaced the power supply and changed the memory module with new one with twice as much ram. but my pc still won't stay on. can someone please tell me whats wrong?