To add to NSGM's excellent tip above, use Windows Backup
(or a third party application) to create a system image. Read this tutorial to learn how: Backup Complete Computer - Create an Image Backup
It is recommend you create a system image before installing any additional software. Personally I have a system where I create an image when Windows is installed, before any drivers
and software. Then after installing drivers, I'll create another image, and after installing all applications and software I'll create a third one. This way I can always restore my computer to any of the three states: basic Windows installation, the same with drivers, and finally a complete installation (I am over cautious, I know
Computers delivered with a pre-installed operating system normally have a Recovery partition
, which allows the user to burn a set of installation disks. Check your computer's manuals and / or ask from the manufacturer's tech support how to do this on your computer.