Thanks kemical!
Unfortunately though the Killdisk didn't cut it.
The disk isn't the problem then, so its a BIOS thing, but I haven't got a clue what it could be in bios!?! (I restored default settings...twice, just to make sure)
One intersting thing happened though when I put in the win7 DVD. I had to reboot a couple times, because after booting from the DVD a screen came up saying:
Non-system disk or disk error
replace and strike any key when ready
This is the same DVD I installed win7 with for at least a dozen times this week, never with this screen. I also tried putting in the XP DVD, same thing. I end up switching everything off, turning it on again, after three or four times, it starts setting up windows.
I beginning to think my machine is fried!
This is becoming illogical.