Just installing certain games can give you no end of grief since some will deposit incompatible .dll's in the windows subdirectory, which can affect displays, sound, and mouse movement. So, it does not have to necessarily have anything due to stress. Having said that, the biggest factor for card failure is heat. Some games will certainly make the machine run hotter. It is not only the chips on the graphics card but the CPU itself. When your heating solution won't keep up, chips begin to fail.

Ah rite so it can effect the graphics gard and the cpu over time because of the heat?

Exactly. Depending on the game the graphics card may be stressed and if the internal temperature within the case of the computer is high, and if the fan (if there is one on the graphics card) gets mucked up with dust, the components on the card may run too hot and cause the card to eventually fail or not be able to keep up. Also, some cards are overclocked by some companies. This makes the card faster, but it also runs hotter. On the other hand, some games really rev up the CPU. The cooling mechanism above the CPU can likewise get encased in dust causing the processor to run hot. Memory chips, the southbridge, all of these run hot. Last (and sometimes the first to go) are the tiny capacitors on the motherboard. They overheat and increase resistance and the computer will reboot at odd intervals. Heat, improper air flow, and dust clogging will take their toll on any machine.

Cool ill keep that in mind:) thanks alot for the info i really appreciate it

Another thing you could do is to look for hardware monitor apps that can read the current CPU & GPU temps. Then run a game and after running this game for awhile just quit the game and immediately check the temps.
 
Do this a few times to get a good mean temp average. You will want to be sure you run the game the same amount of time for each session too
 
If you prefer to let the machine run all night, the d/l and install 3D Mark 2001-SE, this version has the continuous run ability and it does a very good stress test to the system as well.

For hardware monitoring, I suggest Motherboard Monitor: http://majorgeeks.com/download.php?det=311, it writes a logfile of your system temps, giving you the high/low/average temps of the system.
 
Not all vidcards have temperature monitoring, mainly just the newer ones do, and not all of those either.
 
The 3D Mark series of benchmarks are, well, benchmarks, okay, but they are synthetic benchmarks, they don't give a sense of what your videocard will do in an actual game.
 
To stress test your system, get Prime95: http://majorgeeks.com/download.php?det=4363
 
For your RAM, get MemTest: http://majorgeeks.com/download.php?det=350
 
To test your vidcard, get into a game, crank up the eye candy, and play. If you crash your system, check out the MBM logfile, and see what got hot.
 
There are dozens of system monitors out there: http://majorgeeks.com/downloads11.html, MBM being the best in my opinion, but remember, anything that monitors your system, also uses up resources. You can't make an omelet without breaking an egg.