I finalised a disc that I had finished recording,after it had finished the machine locked up and would not respond to the remote or pressing any buttons on the front panel. Had to switch off power at the mains to reset it. Now the disc will not load and just reports 'disc error'. Said disc will not load and play on my pc either. Is there any way to recover it or is it only good as a coaster now?

You'll need to use something like IsoBuster or CD Roller. If it's a write-once disc then the disc itself will be a coaster, but you should get the content back to re-burn.

IsoPuzzle is a very nice donation-ware alternative, but is a bit more complicated to use.