Neowin checked out the How to: Create Windows 8.1 install media if you lost your install disk
A quote from the article:
If you have an installation of Windows 8.1 and you need to re-install the OS but can't find your install media, Microsoft has made it very easy to create the contents you will need.How to: Create Windows 8.1 install media if you lost your install disk @ Neowin
