Hello ip, and welcome to Sevenforums!
First off, you will want to make sure your graphics card and windows (fill out
your system specs with
system info tool) are updated completely, including
drivers (
How to automatically install drivers with windows updates).
If it is a really old game, consider putting it into compatability mode for Vista or XP (
How to put a program into compatability mode). Consider lowering the graphics card settings before playing the game if the previous method doesn't work.
I highly recommend the removal of the terrible thing that some say is an antivirus called AVG. It is not just my opinion and that I am a fanboy of another Antivirus, but I along with many others have witnessed first hand the poor quality AVG program's destructive force. It has wrecked windows operation and internet connection countless times, slows down the computer, and isn't that great of an antivirus to begin with. If you are looking for a good, light, and common antivirus, you might consider
Microsoft Security Essentials, or look here at this thread for more opinions on the matter:
What's the Best Anti-virus?.
If you are interested in removing AVG, you will need to uninstall it with a special AVG uninstaller tool as a precaution against harmful files getting left behind. Find the correct program here: AVG - Download tools and utilities