TBH, it depends on what "stuffed" the machine.
If the PSU had "a moment", then a power surge would stuff an HD and nothing would be recoverble. I've seen one drive failure take out another drive. I've even had the "joys" of a copyright protection wipe out winders, a DVD burner, an IDE card and a hard disk. You have to face the fact that it might be a paperweight.
Bushfiva's idea of "getdataback" is a good one, I've recovered drives and memory cards from cameras using that. Trust me, it's worth paying for. The only othe options I can think of is sticking the offending drive into another PC and seeing what happens, or booting from a Dos floppy and seeing if that recognises the disk.
Otherwise you'll have to send it to the professional people and the will charge you around as much as your children cost in a month.