PC wont load up any of my computer games

A while ago my computer got a virus so i had my mom take it to her job and have an IT professional there format the hard drive and remove the virus. So now that the virus is gone everything works except for the games i try to play. I have tried to play Left 4 Dead and NFS Underground 2. They both install perfectly fine, but when i click on the shortcut to run them, it loads up for a second (showing the picture) and then just stops. The computer makes the sound of it reading and loading the cd but i dont know whats wrong. Any Help Plz

You may have some registry issues as well - in that case, u may need to reinstall your games. You should also backup your existing game files so you won't lose any game progress...

X~