Yeah that bit of software came along with an XP update at some point. All the simple settings are OK. It all worked up til the end of April and suddenly decided not to - I can't pin down what happened then.

The reason you are having problems is that when set to peer to peer node mode the machine is trying to resolve the computer names to WINS.

Delete both the NodeType and DhcpNodeType keys from: -
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NetBt\Parameters

After deleting the keys restart the computer and test.

Those keys didn't exist so according to the article you linked to above I added them. At least I added the NodeType one but not the other. Will look at this again later in the week but at the moment am too snowed under to think about it. Thanks for your help.

I had a similar problem using a Netgear DG834PN wireless/router/firewall.
I COULD NOT get my Vista desktop to LAN with my XP laptop.
They DO however network and share via WiFi.
I think it's to do with the IP settings defaulting to the WiFi.
I think you have to set the LAN IP manually.
I gave up and stuck with the WiFi networking.
Slower but at least it works ;^)

I finally had time to look at this again, read properly what you said and your linked article said, did what you said rather than what I thought you said and I can now talk to the other PCs on my home network. Tomorrow I'll find out if the same applies in the office.

Thank you very much for your help. I owe you several pints.

After reading this, I have also now found that my XP desktop sees my vista laptops but cannot connect to share files. The vista laptops have bo problems netwoking between themselves and the xp desktop.

Do I try the reg key deletion on the xp system?

I would assume so. Look at SSmith's first post and the article linked to - that article was written around XP rather than Vista. You've nothing to lose by trying it - other than your sanity!

No probs ... the joys of using Viista!