Mouse Jerks when playing some games.

I just got a new graphic card, it is a Asylum Geforce FX 5200. The mouse works fine with games that dont require a good graphic card to run for instance Warcraft 3 runs fine even with all settings on high. When I play a game like morrowind the mouse jerks. The game runs smoothly, its just the mouse that jerks. It doesnt jerk that bad ,but it is noticable. I can still play the games but it gets annoying sometimes. I can't understand why. Everything except the mouse runs smooth. Turning the setting down doesnt help either ,even at an extremly low resolution and low detail settings it still happens. The mouse pointer doesnt move at the same speed i move the mouse. I updated drivers for my graphic card as well and it still happens. Please Help!!!!!!!!!!!!!!!!