Hello,
Thanks for your reply. I did as you suggested and the BIOS version came up as AMI 7.02 12/3/2012. Is this the correct version or should it be updated ? I will try a power reset and let you know what happens. The problem is intermittent and sometimes won't happen for 10 days or so, but I will get back to you and let you know if this has cracked the problem.
Many thanks for your help so far.
Kind regards,
Ian