Its the ram voltages. I had the same issue. the Biostar defaults to 1.8v on the DDR2, performance ram operates at about 2 or 2.1v. take one of the sticks out and boot into BIOS and increase the ram voltage. under the menu labeled O.N.E there will be a voltages option towards the bottom, from there you can change all your voltages. Just increase the ram voltage by .2 or something. It took me forever to figure that out.
It can't power the ram without serious errors. The mobo will protect itself and not boot.
Of course this is assuming that this is the problem, there are many things that can keep you from posting.
How are you 100% certain your GPU is ok? You said no video, but everything else powers up.
It's not uncommon for video cards to be DOA. I would try swapping a different card in to see if it works. If it does work, then your GPU is probably to blame.
Try plugging your monitor into the other video card port. It sounds frivolous but you will be surprised how often it works.