Problem with my GeForce GT 440

I’ve recently bought a new graphics card GeForce GT 440. Every time I play 3D games the first problem that I encounter is the game will lag and then there will be a green and sometimes black line on the left screen. I have an updated driver for this which I’ve got directly from NVIDIA web site. I don’t have any problem with my 2 GB RAM. I hope someone can help me regarding this problem.
