RPC Server unavailable error when attempting to print or download software?

This means that this service have been disabled.

You need to re-enable it. Do as follow:

Open your controll pannel. Find and open the services manager, or just services. Should be in the Administrator options. On Vista or 7, you should need to log in as administrator to start that applet.

Find "RPC Server".
It's startup type must be set to Manual, or optionaly Automatic.

Double-click that service and set it to "Manual"

Electro
July 2011