Yeah, everything you have now will be gone. If you have a dell, HP, or some other pre-built system, there should be a resotre disc that will reinstall the OS as well as the drivers. However, if you dont have that disc or you have custom built, you will need to install the OS and find the drivers for all of your hardware components (video, sound, network, motherboard). Windows will install default drivers for most of these things, but there may be some that you have to find. I would install drivers from the manf. website over the MS drivers when you get far enough to do so. The only other thing is any important files you have now will be lost unless you back them up.