Video jerky

I have a packard bell system running the following:
Vista home premium
AMD Phenom 8450 Triple-core processor
3GB Ram
Nvidia GeForce 8400 (I think because since a driver update this now reports as a 9200)

I did a system restore to go back to factory settings and had a failed reinstall so I used the rescue discs I originally created when I bought the system. This went fine but the video driver install failed to so I installed the updated drivers from Nvidias site. All good and I could get the resolution to optimum.

What went wrong is that with Aero enabled I have noticed that the video output is jerky and often when cycling down a start menu list the reaction to the cursor hover is delayed.

My windows experience Index score is 3.8 even here are the full scores:

Processor 5.3
Memory (RAM) 3.00 GB 5.9
Graphics NVIDIA GeForce 9200 3.8
Gaming graphics 1407 MB Total available graphics memory 4.5
Primary hard disk 209GB Free (286GB Total) 5.9

Any help would be appreciated

 

So you sure the driver installed correctly? In Device Manger does it show it with a yellow explanation mark?

 

Oops rolleyes I suppose I should have mentioned that as far as device manager is concerned it is working properly, the Nvidia control panel seems to be fully functional as well.