Hello
Is this a full install of devices?
SLI video or single vc?
What is your psu rating and brand?
Does your video require it's own power?
Try a bare bones setup, to get you into the bios setup.
Check that there is no grounding on MoBo and that you have the
MoBo stand offs (stand offs separate MoBo from case)
Reseat the cpu hsf and be sure to use fresh thermal paste.
CPU, 1x ram, 1x video and keyboard/monitor.
No cdrom, hdd, sound card, mouse etc., unplugged and no power to
these items.
If still unable to get into bios, switch out the ram and video card
1 at a time to eliminate them as problem.
If possible check each componant in another system to insure
they work properly.
Post back
G'Luck