Generally when it doesn't beep at all it's signifying CPU or motherboard problems.
To truly troubleshoot it, pull the mobo out, set an anti-static bag on the motherboard box, and then the mobo ontop of that, plug in the power, the case speaker so you can hear any beeps, keyboard, stick of RAM, and vid card.
Pull out the vid card, if it beeps, then perhaps the vid card is the problem, could be something as simple as reseating it. Same with the RAM, pull it out and see if you do get some beeps. That would indicate the RAM is at fault.
If nothing happens after you've remove the video card and RAM, then motherboard or CPU is lookin to be the problem