|I am not sying this is the problem with your computer just trying to give you an idea of where it could be. Its up to you to do the trouble shooting. |
You have to setup a bench computer (Mobo, Graphics Card and RAM that you know works) Then you can take each of the components off your old system and start applying them to the bench system until you determine which one is the problem. It could very well be the mother board is fried but you will not know that until you put the components into one that works.
This is why I suggest that you take it to a technician to get it checked out because he will have such a system. Me personally, I have a bench system that I can play with when doing these things but it sounds like you do not.