I found out another motherboard that's about 2 and a half years old and I think it was one I ruined. Basically it had a 512 MB stick of RAM in and it worked fine. So I put a spare 128 MB stick in to boost it - which was a bad idea. When I did this, it gave a beep to indicate there was a RAM error so I took the 128 stick out and put it back how it was. Started it up and there was still a RAM error. Now any stick of RAM I try in it gives the same RAM error beep. Can this be repaired or has something in the board blown and it needs chucking it out?
I can't remember if I did now, I could try it again though. It's a P4 board so I'll have to take the CPU out of my working computer to try things on it. This could be one solution though so I'll try that tomorrow.
I just tried a BIOS reset (both by removing the battery and by setting the reset jumper) and it still doesn't start up. I think that combination of RAM probably killed it so I might just chuck it out, unless anyone has any other suggestions.