Graphics problem!

[Plague]

Hey guys,
I have a strange problem, For ages now ive had to run at 30FPS, as When i turn Vsync/ No Vsync on, The game's animations become extremely Jurkey. Its animations only, as the framerate stays higher than 30 FPS!
My PC basic specs are:
Amd 64 3400+
1GB DDR400 Ram
Asus v9950 GE (Nvidia 5900 Chipset)

Any help with this will be greatly appreciated!