Hi Major Disaster. Hope this helps.
You do need to uninstall your previous graphics drivers first. Also, before you install the new one, shut down your anti virus so the new drivers can configure properly. When your on Nvidias' site, select driver updates at the top, go through the 3 steps and then click on download tips (or similar) on the left hand side which will explain anyway.
When your happy to start, click on primary download site, accept the agreement and off you go!
Bear in mind that when your old drivers are gone, your computer will switch to a basic graphics system so you may find things a little slow until your new driver is in.
Let me know how you get on.