Whats the story with this? Game is becoming totally unstable after a relatively low time played.

Windows Vista x64, nVidia GTX275, 4 gigs ram, plenty of CPU and hard drive

After my most recent save game, every time I try to load I get maybe 1 minute into the game and CTD like clock work with a "program has had an unexpected shutdown, windows is trying to figure out why..."

post 64-bit dxdiag please
use any mods?
try to restore a .bak save (move/delete/rename the old one and jsut remove .bak on autosave or quicksave)
Yoursave games are in
C:\Users\\Documents\My Games\FalloutNV\Saves