about 5 days ago when i tried to run 3d games (battle field 2, CoD 4) the games would freeze at a random time usually within 10 sec to 10 min of running it. and about 0.5 sec of the sound that was playing would repeat it self really fast while the screen was frozen. i couldnt exit or open task manager so i would have to force shutdown, then start up again and try and play the game again, then after a while of me repeating this, on start up windows froze (like when it had pretty much finished loading, the start bar was up and some of the icons loaded) it happens every time that i turn on my computer usually within 5 sec - 12 sec. sometimes the screen would make a retarted coloured pattern all over the screen usually pinkish/yellowish but sometimes blue/yellow and other random colours. im guessing it has something to do with the graphics card?

Sounds like your graphics card is going south. Open up the PC case and make sure the fan on the video card is spinning, and go ahead and blow it out with some compressed air. You should try updating your video drivers and patching your games as well, but odds are this is a hardware problem.