Weird system shutdown on startup.. Help!!


Jun 24, 2009
I built a computer using all components from my older computer which worked perfectly before, just sold them to a friend and he asked me to install it into his case. Anyway i finished and pressed the power the button. The computer starts, i get the post screen message then 2 beeps and it automatically shuts down.
The weird thing is, the first time i press it, it goes to the select windows screen, then 2 beeps and automatic shutdown. Then when i press the power button again, it reaches the post message and 2 beeps and shuts down, the more i press the button the least time it is turned on. Eventually the instant i press the power button, it instantly shuts off.
But say i wait about 5 minutes and turn it on, it all repeats. Reaches windows select and shuts down, so on so on untill again i have to wait 5 minutes.

The only different parts that are in the computer from what i had before is the standard q6600 cpu fan (i had watercooling), my friend bought a 750w psu (i had 700w), and the ram is brand new.. I think its not the ram problem because like i said at first start after taking a break it passes the ram check, then 2 beeps and so on. The weird part is that everytime i turn it on, the time between shutdowns gets shorter?? Please i really need help, need to solve this.