Do you have a system speaker installed so you can hear the beeps? Many motherboards and cases don't come with them anymore. That's a pretty old motherboard. Did it beep at boot when it was working correctly?
Here's a checklist that will help you narrow down what the problem could be:http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems#t1895014