I've received a reply from him as follows:
Hi Clive,
Thank you for this information and your support.
I have removed the virus and it did require a low level format of the hard drive. This meant I had to destroy the recovery partition on the computer with the factory preset recovery program. Unfortunately the virus was living in this partition. So I had to replace the operating system since the recovery disc was rendered unusable - not a cheap or cheerful
solution!