Nope this is not a gimmick.I have been a member here for a few years adn run most games without any issues at all.
To start with make sure you install any extra software a game needs.Links to any supplemental software needed will be linked to from the games own page.
Even though you are using win 7 you will need to install direct x9 as lots of games here will need it in order to function correctly.It wont replace or delete dx 10,11 it will just simplly work along side them.
Make sure you are using up to date drivers for your system.This can include gfx,sound and mobo drivers.
Check that your security software is not blocking the player or game from running
Make sure your system is clean of malware.Along side my security software i use advanced system which is free and available from http://www.iobit.com
It scans spyware,invalid reg entries etc and removes them.I alos use malwarebytes anti malware.
Another utility you may find usefull from iobit.com is game booster.This utility closes down background applictions and frees up resources so that the games can make use of them.
If after tying the above you still have issues running any games then reply here letting us know what games you have issues with and as much info about the issue as possible and im sure either myself or another one of the regular posters here will be able to offer you some constructive advice.