Why does my video card just freeze in the middle of games?

Whenever im playing a game in my pc, my video card will just go slow motion (like 1 frame per second). I dont know whats wrong with it. I have a PCI-BUS Nvidia geforce fx5500 128mb. I have tried to install all the drivers, and I even reinstalled windows on my pc but it keeps doing that. Any help?|||Many things could be causing this. It might for instance be a sound issue, turn down your sound acceleration in directx, you also might try different directx video acceleration, you can reduce the the video and sound options in the games, you might also turn anything off that is loading at startup or running in the background.|||Could be a couple of things but I'll bet it's a memory issue. Games require tons of RAM. Pull up you process monitor (CTL ALT DLT) and watch your memory usage in the performance window. (And watch the processor graph) Do this in a separate window so you can play and watch the usage at the same time.|||Sounds like a heat issue. Buy a can of compressed air, open up your PC, take it outside and blow all the dust that's inside the case away. A can will cost you about $3, and if you haven't done it already, it's a good idea to do it about every 6 months. Dirt can get into all those little spots in the heat sink and clog it up, heating up your system and reducing it's life span.|||you need more ram