how to uninstall nvidia and install amd radeon

[eyeshield29]

im planning to buy a new graphics card (amd r9 280x) and switch it with my old gtx 640... i know i need to uninstall and install new drivers but im not sure how to.

 

[yakamaster]

in control panels programs and features remove the 640s drivers and install the new ones..you will find your existing driver in programs and features