Thanks Kephnir. I'll get this marked as ANSWERED for you.

PCHF has several good hardware techs available to assist if you plan on rebuilding yourself. AW_3_3 seems to spend all his time searching for great deals on incredible hardware. I would be happy to refer you to him if you wish ;-)

Best of luck locating either the parts or a new system.

kephnir, i have a bit the same problem as you, but my specs are higher then recommended, i think there is some sort of bug in the game, because when i leave the vault, it works perfectly, but when i leave megaton or talk to moriarity, it crashes and gives an error, and i was hoping if someone could help me too, i posted a threat too, because i thought it might be my video card, there was an whole list of video cards that are compatible with game, but mine wasn't in there, it's an geforce 9500 gs

can someone please help me?
KInd regards Thony