Computer restarts

What is wrong with this one?

“alright, it worked earlier today, then went in and changed some pipeing for my watercooling. when I was done and hit the power button it would turn on for a few secs (no beeping at all) then shut down. I can turn it back on right after it shuts down. but just repeats shuting down.

i have removed all power cables but to the motherboard and the video card but still have the same problem.”