heres a similiar thread, see if you can try any of the other idea's suggested.
http://www.tomshardware.com/forum/25...-q9450-nothing
If you removed the ram and still hear no beep errors, I think either the speaker isn't hooked up correctly or the mobo might be croaked. I would try assembling everything outside of your case on a box or something similiar.
I had a similiar problem with my old gigabyte when I accidentally shorted it out (as far as I know), it would boot up lights come on but nothing more. Was really leaning towards rma'ing the vid card before hand.
One would think if its the video card at fault you would still hear the hdd's spooling up and perhaps the audio from windows loading.
Perhaps you could take your vid card into a local shop and ask them to see if it outputs video. That would almost certainly narrow it down to the motherboard IMO.