have you tried without the graphic card? use onboard graphics?
also try envoking the backup bios to kick in
do this by holding front power button in and flick on the psu power button on and flick off as soon as the fan spins,do this two or three times then let go of front panel button and let pc boot up,you should see a message saying the backup bios is being flashed to the main bios
then see if it still loops