Networking was working in the past.
Each computer has Kaspersky Pure 3.0 installed.
There have not been any changes made to the network.
Kaspersky 3 is automatically updated
Networking established on two laptops with Kaspersky Pure 3 removed
Thanks for your suggestions, I think I will have to take up the problem with Kaspersky's Support People as I have tried all the settings I can change without success.
OK. If you would care to rate my Answer, that would be appreciated... and would allow me to be paid for the work I have done on your question.
What little help I can provide for Kaspersky is on this page:http://forum.kaspersky.com/lofiversion/index.php/t159622.htmland it says go to Kaspersky Settings, click onFirewall - Settings - Networksand then set your home network as 'Local Network'.That page also points out that if your local network, on the Windows side, is set as 'Public Network', then that is wrong, for that disables local network file sharing.
I eventually found the option to change my connection from Public to Local on each of my computers and this has overcome the problem of communication between them with Kaspersky operating on all three machines.
Many thanks for your advice