It's pretty straight forward as long as you have backed up all your files, email files, settings that you want to keep once you have reinstalled. The other thing you need to back up or download before you start is the drivers for your hardware otherwise you could end up stuck.

If you have bought a branded computer, you will more than likely have to reinstall with a branded operating system which will no doubt contain a load of pointless programs which often run in the background using up valuable memory and processor power and would be better to uninstall these.