Welcome to Tom's Hardware Forums,
We have a start there, mind telling what happens when you press F4 or does that ruin the fun?
I'm guessing the computer starts. Do I win?
Sorry, tired, really though, what does happen after pressing F4?
on newer pc the mb check to see if there a floppy drive installed in the pc. you see this at post when the bios makes the floppy drive and cd-rom drive blink. if there no drive installed and someone tells the bios there is a floppy drive installed you get that error message. if there not drive go into the bios and turn off floppy drive. if there is one power off the pc and power it back on..if the floppy light on hard...then someone may have pulled the cable off the drive in an upgrade and put the cable on wrong.
if the light does not come on..open the case and see that both the data and power are connected.