Problem found!! I think!
I was going to try some of the advice that was given but before that I said, one more try to see if it still freezes.
Then it hit me, the SCREEN SAVER was activating after 5 minutes and was or may have been causing problems with the game!
Also after doing some diagnostics, I found a sound (wav) driver for a voice fax/modem was not being used and it was suggested that I uninstall it. I just dissabled it insread!
So, so far so good *knock on wood*!
GREAT game, I hope it won't be long before I'm playing MP online!
Stephen