has anyone seen this problem?

My oldest pc seems to have a virus and I thought I got rid of it but I noticed it running slower than normal and when I go to the control panel to add/remove programs its very weird. It shows a couple programs then it has a long long set of black and white thick vertical lines after then it shows the rest of the programs. I've never ssen this before, has anyone else? So I figure I didn't fully get rid of the virus or not.