The most radical solution is to install Win'XP. But the problem is that there can be many reasons for the issue: starting with the fact that the OS is Windows 7, and then: - a pirated or unstable OS; - pirated or unstable versions of the games; - a lot of software is installed, some of which works incorrectly (typical for "custom" OS builds!); - outdated or faulty video/audio drivers, etc. It is likely that only a specialist who can analyze the situation on your computer can really help.