Are you still getting green screens?
Assuming you've done what the guys above have said (insert CPU card, reseat socketed chips, make sure RAM chips are good by testing on another machine), then one further reason for a green screen could be a leaking SMD capacitor near the battery (speaking of batteries, I'd remove those ASAP, because they will kill your motherboard one day, almost certain). After cleaning up the blown capacitor and replacing it, it worked like a charm again. In fact it'd be a good idea to replace all SMD caps on those motherboards. They will leak eventually, and even if you can't see it, they might be leaking already. I've replaced all mine with tantalums and won't have to worry for 100+ years (wait - I'll be dead then!)
Good luck!
PS. if you need more info, contact me
