you need to download the coolbits registry tweak or rivatuner. Rivatuner is possibly your best bet. If you need to ask that kind of question though I wonder if you should be overclocking your video card. If you decide to go ahead and do it take it slowly. Go up by no more than ten percent of your stock speeds. Take is up to that limit by 5 Mhz at a time, If you get artifacts on screen or tearing you have taken it too high. If your unsure of what you are doing dont risk it. Its an xpensive hobby. If you need further advice post back. If you go over 10% expect the worst it isnt likely to happen I run my TI 200 at 249/526 the stock speed is 175/400 its happy although it will die a lot earlier than it otherwise would do. Your PC will also generate a lot mopre heat than it used to do so if you get other random crashes your pc could be overheating. Be careful and be safe and you will hopefully be ok.