Hi unvi$ible,

Can you boot it from a floppy disk or CD?.............. you may need to disconnect the hard drive cable first.

It sounds as if your BIOS is corrupted, or you have serious motherboard problems. If you cannot get in and re-flash the BIOS then I am afraid that means a new MoBo.

Try looking on the MoBo to see if you can reset the BIOS with a jumper switch, please consult the manual. Otherwise disconnect the machine from the mains power, take out the CMOS battery and leave it for a day, then put the battery back. With a bit of luck that will reset the BIOS to the factory defaults, and the machine will work again.

It would be a good idea to test the battery as well.