can't system restore can't do disk cleanup,defrag and screen gone blank but still have icons can't get themes to work and when i do a ctrl+alt+del i get a message saying task master has been disabled by your administrator sort that lot out i'll donate my wages thanks........

In the future please include some clue of what the problem is in the message title. Thanks

To start on fixing your problems I recommend you run sfc /scannow. This will scan for and fix or replace any damaged or missing Windows files.

How to use sfc /scannow