Whenever I try to download the Desktop' appears on the screen. I have tried to 'System Restore' but again am unable to do so. I have recently installed CCCleaner and changed my router (Voyager210). I suspect Registery problems. Any help would be appreciated. With thanks.

As a first response you might want to post a HijackThis log for review by our Pros in that section:

Please follow the instructions HERE & then post your log in a new thread in the Spyware, Adware, Viruses and HijackThis Logs section.
(Not in this section please).

Please specify what issues you appear to be experiencing along with your log.