SME to XP Networking problem

I have SME server set up on a fast machine (1.7Ghz)
I have XP Pro set up on a fast machine (2.2Ghz)

XP is the Internet gateway and SME is the fileserver.

My problem is that Windows Eplorer hangs for about 10 minutes on connection
to either the server or the internet. I can run software but all the button
clicks on the taskbar are ignored for about 10 minutes. Then they all come
through in a rush.

Any suggestions? The system checks out as OK with Norton.

--
Yours

Widow Twankey

** now shacked up with the Giant Beanstalk **