Hi,
Whilst waiting for your response I noticed that my PC was doing some strange things; icons were missing, programs not working correctly etc so I decided that regardless of the fault, I would do a wipe and clean re-install. All my data is stored on separate drives which I've currently got disconnected from the main PC. Once I get the OS re-installed and Avast up and running again, I'll plug the other drives in and do a fulls can of each to check that they are clean.
Thank you again for your assistance, without which I wouldnt have been able to get back to my desktop and back-up some important program settings and folders. Even though I have my personal data on a separate drive, it also gave me the opportunity to back that up as well, just to be sure :-)
Top marks :-)
Matt