So where does the video game come into play here?
The quickest solution would be: backup, then format then reinstall windows.
Removing this piece of software could be a hastle so you might spend weeks until you succeed (and you might not) . Since you say it's slowing your PC down, then that means its constantly running in the background.
1. dowload a program that allows you to see which programs are running when you start your PC. "Startup inspector" is one such software.
2. Run this software and try to see which startup entry might be responsible. you'll need to do a lot of trial an error. Basically untick most things that are not vital windows progs, then try ticking and restarting again to see if your PC has slowed down again.
Eventually you'll find the registry entry responsible for starting the evil program. Upon deleting that entry, and starting your PC again. You should be able to delete the program if you know where its files are located.
by the way.. how much money has the program made for you