Turns out if you remove a file\service called wdf01000 you will be greeted with many devices with yellow ‘!’, and many will simply not work.
Some examples include processor drivers, CD\DVD drivers, mouse and keyboard that are USB (ps/2 works fine), and sound drivers.
First off, we need to restore the file wdf01000.sys to C:\windows\system32\drivers. For Windows Vista\7 simply right click and go to properties -> Previous Versions -> and select a previous version and open it. Copy and paste the older wdf01000.sys into the C:\windows\system32\drivers.
Now just merge this key For Windows Vista or Windows 7 [32-bit tested only]
Windows Registry Editor Version 5.00
“DisplayName”=”Kernel Mode Driver Frameworks service”
Why does this happen? Well, take a look at the definition for WDF:
WDF implements the fundamental features of a Windows driver and enables you to focus on the specific details of your hardware or filter. WDF defines a single driver model that you can use to create object-oriented, event-driven drivers for either kernel mode or user mode.