I can't make any changes to Windows Features. Even if I just enter in Windows Features and press Ok I get: "An error has occured. Not all of the features were successfully changed."
I noticed this while trying to install/uninstall IIS. If I try to install IIS from the Web Platform I get:
[Windows package manager]
The referenced assembly could not be found.
Operation failed with 0x80073701
I have tried
-> Startup Repair. It says it has found problems but is unable to solve them
-> System restore (but didn't had an early enough restore point)