Workgroups not working

This is at the office. Total of 10 computers, all running XP Pro. We do have a switch they're all tied to with our internet access coming through it. They are all in the same workgroup for file sharing.

The issue, half the computers just quit being able to access the workgroup. Last time it happened, starting changing the workgoup from 'abcde' to 'abc' and after 5 of them were changed, the entire network came back online and all 10 computers could see each other, no matter which workgroup they were in. Changed those 5 back to 'abcde' and they all still worked. Now a week later, 5 of the computers cannot see (or do not have access to) the local network, but all can still access the internet.

It's not the same 5. In fact, the 5 that have access can still access the ones that can't. One machine that still had access yesterday, in the middle of transferring some files from one machine to another, the entire network just disappeared from it.

I'm at a loss, it's just been too many years since I had to deal with this kind of stuff.

Is there any kind of software firewall on the machines? I am assuming NetBIOS is turned on in every machine? Is the Computer Browser service running on all the machines? Do you have another cheap switch you could throw in the network just for troubleshooting purposes? Also, check the node type in Windows with the ipconfig.

don't have access to the switch right now. It's in a closet I don't have a key for, and currently the only one here due to the little ice storm we had last night.

Yes, the boss has installed pos McAfee Total Protection on all the systems with it's firewall and the Windows firewall running on all of them except mine since I turn it all off when he's not looking. Did try turning it all off on two of the machines, still without success at getting either of them back to seeing the network.

NetBIOS is not turned on, on any of the machines that I have checked.

The problem might be the other machines are not allowing themselves to be seen because of the McAfee crap (i.e. turning it off on a few machines and then browsing from them might not do any good). Turn it off everywhere (McAfee and Windows firewall) for troubleshooting and turn on NetBIOS. Reboot all the machines after that and see how things look. If it does work, start turning things on until it breaks again.

Found it. 5 of the 6 machines I have access to right now were not getting on the network. Decided to shut down the one that was on the network. The network popped right back up on the other 5.

Turned that one back on and 'someone' had the McAfee firewall connection type set as "Untrusted Network". Changed it to 'Trusted Netwrok' and all is well again.

Pick up a new machine, load Windows Small Business Server and now you have a domain and a real system. SBS is very inexpensive and gives you MS Exchange, Outlook Web Access, firewall and remote access to all of your workstations, and no more workgroups. You can get it preloaded on an HP or Dell server. Maybe $2500 total cost.

I've talked to the owners about that several times over the past few years - no go. It works well enough and they have me around to figure out the few issues we run in to. They've only had to call in outside help once in the 8 years I've been here, and then only because my work load didn't allow me to waste my time looking at computers.