first read this please:http://www.gamesas.com/topic/1506391-fallout-3-crashing-in-the-please-stand-by-slide/

I have "fixed" this problem,but now when i press new game the game crash while in load screen

Normally it runs on windows 7 right after installation

Seen your dx post on the previous message.

Try to lower the graphic settings and disable vertical sync. But it seems it is a global problem with your system. It can run with intel graphics but very poorly.

Perhaps it exists a mod for low-end systems like OldOblivion for fallout

Otherwise, have a look at the teaking guide here http://www.tweakguides.com/Fallout3_1.html

Well, edit again. Made a search for oldoblivion/oldfallout and found this. It may be interesting but I can't say what it's worth

http://www.tomshardware.co.uk/forum/115298-13-fallout-crashes-making-saved-game