If the motherboard is a recent asus one, it has a BIOS restore function it, activated by the disc that came with it.
Panic over. It's a Gigabyte motherboard. Wasn't aware that there was a backup BIOS but I am now! Wouldn't boot up, turned the power supply off and stuff and then it told me that the main BIOS was corrupted and proceeded to overwrite it with the backup one. Sometimes I love technology.