I think you have some corrupted or bad file / setting, either in directx , or video drivers, or the game, or ultimately windows.
If the game runs normal to you with your memory,
if i remember right minimum spec. for sh3 is 512 mb.
Try this:
I suggest updating directx, here:
http://www.microsoft.com/downloads/d...displaylang=en
Then the newest drivers
for your card are here:
http://www.nvidia.com/object/winxp_169.21_whql.html
- And wipe out the sh3 from the pc, and reinstall it again.
That should do it. Good luck.