mine is agp nvidia 5200 w/128mb.
Minimum required for Fallout 3 is a 6800. It's not going to run on that 5200 (Which is more of a business card)
the only way to upgrade is to get a new computer loaded with win7.
Doesn't have to be one with Windows 7.
the shaders can't be turned off in the ini files?
Probably not. Since the game depends on them to produce the graphics it would just crash before you got anywhere close to the game.
like i said, i don't mind playing on lowest reqs. es4 world on lowest w/disabled trees and grass looks like fallout 3 world on highest
No it doesn't. Fallout 3 graphics are higher detailed, the viewing distance is long and better streamlined, visual effects are better detailed. Just because there's less colour (To represent a nuclear blasted wasteland) does not been the graphics are less detailed.
In any case, even with every setting at the minimum and the ini tweaked to the ceiling, it still isn't going to run.