I am getting help from AVG's online forum to remove a virus from my laptop. They have explained I must boot the laptop from their AVG Rescure Disk which I ave burned onto a cd. Then I select Utilities and 'Fix MBR' - then select 'overwrite MBR'.
Can I check if this sounds correct because it just occurred to me that overwriting the Master Boot Record might delete all my existing files?
Fixing (or even deleting) the master boot record won't touch any of the existing files on the hard drive and as long as the MBR is rewritten correctly the computer will be fine... and, even if the MBR isn't rewritten properly by their software it's not too hard to fix the problem and your files will be safe.
I presume you've got a boot sector virus, in which case go ahead and do as they suggest.