Custom Build does not boot, blank screen

[foaf]

EDIT: A complete rebuild seems to have sorted something as I'm into the BIOS. At the risk of wasting anyones time, could this thread be deleted?

Hi all, I'm having a bit of a shocker with my custom PC. Upon switching on all fans have power (Case, GPU, CPU), the mobo's LED lights up. The screen does not come out of hibernation.

I have used a POST [code] card and its giving a resting value of "7F" which apparently means "Extended NMI source enabling is in progress". The display gives a range of codes before resting on 7F. I have removed the graphics card and all other PCI expansions and still the same reading. I know nothing about POST codes and wondered if anyone could indicate what that means.

The case or mobo did not come with an internal speaker so I don't get any morse code bleeps.

I'm fairly certain its noting to do with the graphics card, as the keyboard 'num lock' does not light when switching on. Which leads me to believe its a RAM or CPU problem.

I'm currently taking it all apart and reseating everything, but has anyone got any suggestions on what to test next?