Please help! Its about Open Gl and existing Drivers!!!!

Okay, I am having the problem everyone else is with the Open GL on windows XP. Now, I have downloaded a new NVidia driver. I go to download it and it says that I have an existing driver and that it is recommended that I delete the existing one before installing the new one. My question is, where do I go to delete this and how? Please help men, I am driving myself nuts not being able to play games online. Damn this sucks. Any help will be appreciated.