Troubleshooting Mysterious Horizontal Green Bar

I installed NFS Most wanted a month ago. When I installed it there appeared a horizontal green bar on the left hand part of the screen extending the entire length of the screen. Basically it's a translucent green encased in two white lines.

Problem is, is that this bar is appearing in all my other games. I was able to eliminate it in FEAR by fiddling with the resolution or resetting stuff to default but in other games I just can't get rid of it.

Any suggestion?

Thanks in advance

Dean