I'm not terribly familiar with all of the different POST beep codes, but my first guess would be either the RAM or video card. First, make sure everything is properly seated, and then try booting. If that doesn't help, you can remove components to help diagnose which is causing the problem. Remove the RAM, boot up, and see if you get the same beep code. Do the same with the video card, etc. You'll just have to keep eliminating components one by one. Let us know your results. In the meantime, some of the more hardware savvy users will surely come along with additional suggestions.
