Problem fixed!
Problem caused by Norton Internet Security 2010 - I had used Norton to uninstall McAfee.
Tried Norton tech support and they couldn't help at all, they suggested that I go to the vendor of the PC and that problem not caused by NIS 2010.
However, contacted tech support at PC World (the vendor) and they were excellent and identified the problem instantly and guided me through the corrective steps - took about two minutes. Apparently it is a common known fault with Norton - requires register editor fix.
From memory, I believe that the following are the steps to resolve the fault:
Type regedit in search box.
Computer
HKEY-LOCAL-MACHINE
SYSTEM
Current Control Set
Class
Then in RHS box two files had to be deleted: lower and upper (can't remember exact names of the files).
Upon reboot problem fixed!
Thank you JW Stuart for taking the time to suggest possible solutions.


