is there a problem with my video card? Virus maybe?

This iMac i work on at work is having major display issues, the finder sidebar and menus at the top are something from the matrix it looks like. I can see some of the stuff in the finder but not all its just very weird. I really cant explain so i have pics to show you. I dont remmber the model number cause i cant see it, but i think its a late 09 maybe, anyhow sorry about the photos i had to take them from my phone as it was impossible to take on the computer itself. The dock is fine and the desktop wallpaper, but not the finder windows and menu items.