Get your mobo manual and open your case up.
Do the following (after you change something - eg reseat the RAM - try a reboot to see if you can POST or get beep codes):
Check that your system speaker is properly connected.
Check that your RAM isn't loose.
Remove everything but the RAM, CPU, Video Card, fans and power (please don't get offended, I've had people remove the PSU before while I was talking them through this).

If you still get nothing, I'd suggest taking your computer in to a technician, as it looks like the mobo is gone.

i did all that and i have the same problem. i was once told that whenever the power supply go it take something with it and i think it took the mobo

well i know a little about it but i was not sure on what do because it was the first i came across a problem like this but thatnks any way for youe help