First off i would check all cable connections. If they are all in ok - consider a drive may be bad.
Try this too, unplug all IDE drives, you should then get a different error or message.
Check your power supply. Maybe voltages are causing it to not function properly. Bad power supplies can cause a multitude of different possibilities.
So start at the basics:
-Power Supply Unit
-Remove other unnecessary peripherals (sound card, network card, modems, etc)
-Test your RAM (MemTest 86+) or take it out and swap around