I'm resetting a Windows 8.1 PC. Media is Windows 8.1 (same DVD used to do the original install).
I've renamed software and system files in c:\windows\system32\config per Microsoft's instructions, which then say to run the "Reset your PC" function.
When I run Reset Your PC, it asks for the "installation or Recovery media". I put in the same DVD that was used to do the original install (Windows 8.1) and it says, "The media inserted is not valid. Try again."
What's going on, and what is the workaround?