Boot Problem!! HELP

Ok, just recently my computer has been acting up on me. Dunno what the problem is, but it wont boot up...just goes straight to a blank screen with a blinking cursor in the top left. I've tried another hard drive and it does the same thing. Dunno why it just decided to die on me like this. Anyone know what I can do? Thanks in advance!

 

Well, my pc is a compaq, 2.8 ghz intel, 40 gb seagate hd, 512 mb ddr, nvidea geforce 4400 128 mb video. I turn on the pc....it gives me the normal bios beep as is it is booting normally....i dont see the bios screen at all...just goes straight to a blank screen with a blinking cursor. After numerous attempts to boot...after unplugging the hd....waiting a few secs and trying again...it will eventually boot into xp and run fine. I have no clue what to do.

 

Have you tried a new IDE cable in there

Maybe download the seagate diagnostic tools and try to test the drives fitness
http://www.seagate.com/support/seatools/