Often these types of malware not only hide all of your files, but reset file permissions and local policies so that you can’t do many of the things you need in order to properly operate the computer after it is cleaned.
To reset all of the policies and permissions on a computer to their windows default, execute the following command from the Run prompt or Command prompt:
secedit /configure /cfg %windir%\repair\secsetup.inf /db secsetup.sdb /verbose
It takes a while to run, and be warned, you may lose some customized settings, but you should be able to make changes to the system after that, unless your windows network has group policies that get applied when you login.