Remove and reseat graphics and sound cards, and although the ram worked, remove it and try one stick in the machine on its own and then if it still doesn't work remove it and try the other as I had a similar problem with my machine.

Also remove and reseat the CPU.

If you still have problems then it's very likely you have a faulty board or HD.

You could also do a BIOS reset by setting the jumper then removing and refitting the battery and putting the jumper back (sure you know how to do this but thought I'd write it out anyhow.)

Let me know if that helps at all Paul.