lol... your computer's Specifications. The CPU (Processor), RAM (System Memory), GPU (Graphics Processing Unit / Video Card) and the resolution you normally run the games at (such as 1680 x 1050, 1280 x 1020) We need all that info to better assist you with your problem, since we can't magically know all that.
I assume you do not meet the System Requirements for the games, since you want to use 3D Analyzer?
You can't use 3d analyzer for the games that require Shader model 3.0 as 3d analyzer supports upto SM 2.0 only. 3d analyzer just disables the starting error in some of the games that's all, the rest is upto your graphic chip or card that you are using to run the game.
The best thing here is to buy a really cheap card and not to loose the real experience of the games like call of duty 4 modern warfare by playing it on low resolution and with low frames.