no beeps may signal bad mobo ... not making it far enough into post to test ram and video
if you take the video card out and the ram out, fire it up with just the cpu and power supply ... if things were working correctly, you should get beep codes informing you of specific things, such as ram and video issue.
no beeps ... may indicate problem with mainboard
i assume you have tried another power supply? reset the bios? reseat the cpu and check it for bent pins? any swollen or leaky capacitors on the board?