Hmm didn't quite understand what you said.
When you press the ON button it beeps 8 times, really fast? then reboots? Or it boots, beeps once, reboots, beeps once.. continuously?
Load of things you can try mate. Need more info from you...
Full system specs? Mobo, cpu, gpu, ram etc. Try booting with one stick of ram in slot 1/2, switch the ram around but only have 1 stick in for boot.
Is this a new build? Has it worked previously? Have you installed any new hard/software? Have you put thermal paste on the cpu? (5mm drop)
Basically just give us a lot of detail about your system, your knowledge of pc's, how this has happened, try removing everything not needed for boot, eg hdd, gpu etc. You should be able to get into bios, load optimized defaults if you can.
Post back with more info...
MiiCK.