I downloaded the world community grid today and it worked for around 27 minutes straight as I ate dinner and washed dishes, but when I returned and came back from the screensaver, there was a pervasive static that blinked across about the upper third of my screen. I was very worried that I'd downloaded a virus and am currently running a scan, but I want to know if this happens often and if this can be resolved.
Once I stopped the program from running, however, the blinking static stopped. What is going on?

I am uninstalling wcg until further notice.