Windows 8 has a very helpful built in refresh tool which re-installs windows without destroying your personal files and windows settings. Any apps that were not originally installed with the OS or downloaded from the Windows Store will be deleted and an HTML file will be created on the desktop detailing what software has been removed.
This tool is extremely helpful in many cases. If the computer is missing certain drivers or the OS is incorrectly installed, using refresh can make for an easy quick-fix.
For a step by step walk through on using Windows Refresh:
http://windows.microsoft.com/en-us/windows-8/restore-refresh-reset-pc
For more information on what Refresh does and how it works: