SD
Thanks for that; both computers now recognise each other and I can access the internet from the guest via the host. It was a firewall problem.
What I am not able to do is print from the guest computer. Both computers have 'File and printer sharing' checked as suggested. The webpage you suggested I look at gives the following advice which I don't understand:
"Cannot Print to a Network Printer after Adding ICS
After you add Internet Connection Sharing (ICS), you discover that you can't print. This can happen because ICS uses a Class C subnet with an address range of 198.168.0.x. To solve the problem, give the printer an IP address to match the subnet of the client computers."
How do I give a printer an IP address?
Thanks for your help.