No you don't need to uninstall everything, but it also is not an update. It is an optional download (which I highly recommend). It did not screw up my computer, but Halfhuman's advice is good. Just search sp2 on the microsoft website, and download it. From there it will uninstall and install anything it needs to...you don't need to do it manually. After you do that, see if wmp 10 works. If it does, you should probably keep it. However, if you are really into music (and have hundreds of songs) wmp 11 may be better for you, since it runs faster with more songs. I do not really like it, but it functions fine.