Did this start happening after you received Ironside's RSQ entry?
Has he infected me?
Thanks for all the suggestions and words of doom and advice.
I managed to get it running by a constant repetition of TIOATIOA and then left it for a while, obviously that meant it hibernated and wouldn't wake up so I now have RSI from a further bout of TIOATIOA but it is on and the power save settings are all set so that it won't sleep or hibernate or power off until I tell it to (or it overheats...)
Meantime I'm looking for places to store what little stuff on it that is worth saving before attempting to work out what needs to be done to fix it properly.