Yes I have tried both IDE and AHCI, neither worked. It's currently in AHCI. Parents is a good half hour drive away. I've spoken to a local PC repair firm this morning and although it's against my normal practice, I may take it into them. I'm at the point where I'm a little beyond my ability and mobo/processor/PSU need testing. They'll diagnose for free, but said it wouldn't be in their interest now they know I'm a self builder, if I'll just take it away and replace the broken component myself. I may therefore swallow the £30 cost of replacing a motherboard for example just to get this machine repaired as I'm not keen on buying replacement parts 'in case it's that bit'.