Generally that will signify a bad motherboard, but it may also do that if one of your sticks of RAM is bad. Generally it won't show the post screen if RAM is bad though. Try it with one stick and swith them, to rule out RAM Memory. I don't think a bad hard drive would cause that because it would still be able to get to the BIOS screen. What are your full specs, and how big is your power supply?
Also, try resetting the CMOS pin on your motherboard.