Question : Problem: My Computer Can Not Open

When I open my computer, It doesnt have Bip sound which every open I have. And nothing in monitor. But fans and hdd and cdrom are working. I try to change Ram and Graphic Card from my other compiter but nothing changed. I take BIOS battery and wait. And nothing changed again. What it could be?

(problem starts with my mouse freeze but keyboard was working. I restarted comp and it can not open now.)

Thanks for Help...

Answer : Problem: My Computer Can Not Open

If it does not beep, it should be:
1) Dead CPU (after overheating or something)
2) Dead motherboard (check if capacitors are not deformed)
3) Dead PSU (check voltages when powered ON using multimeter, should be +-5% of the target values). It might still produce 12v, but have dead 5v lines.