Your symptoms indicate a likely problem of communication with drive electronics. It matters not what you may have scribbled onto sectors. No MBR, no boot, as far as your BIOS is concerned. But you were expecting to boot from other media, and don't get that far -- the BIOS hang is most likely when it tries to communicate with the drive during hardware probing, which doesn't read from media.
Drive electronics communication failures have three likely causes -- for IDE (aka PATA) in probability order:
- Bad IDE connection or cable
- Bad drive electronics
- Bad IDE bus electronics on the motherboard.
Start there. Look for a bent pin, swap cables, etc.