Choose the batch file for your OS and double-click it. Read the warning and press a key. Sit back and wait. A new folder is created on your C: drive called "olddrivers" and files from several system folders are backed up into it. If you have another drive in your PC you can move the folder to that to keep it separate from your system drive. When you re-install Windows and it asks for drivers you just need to point it to this folder.