PC Keeps Disconnecting from Workgroup

First of all I feel I should state that I am by no means an expert when it comes to networking so apologies if I use the wrong terms etc.

OK here's the problem... I'm doing a favour for my mum's boss. The guy that implemented their network has moved away and she has asked me to fix a small problem. The title says it all - one PC keeps somehow disconnecting from the workgroup.

Here's the details: small office peer-to-peer network, involving 4 PCs all running Windows XP Professional. They're all connected to a gateway/adsl router to connect to the internet via normal ethernet cables. I have setup a workgroup and all PCs can communicate with each other. One PC has a local printer attached to it. I have installed this printer on all pcs however after a day or two the pc with the printer attached somehow leaves the workgroup and the remaining pc's can no longer print to it.

More information: All PCs have Norton AV etc. and I needed to temporarily disable the firewalls to install the network printer.

Please please please... can somehow suggest why the PC with the printer attached to it seems to leave the workgroup? I have installed it so that it's working fine - restarted the firewall, rebooted etc and everything still works - however after a day or two it's back to square 1.

All help is greatly appreciated !!!

Regards, Jamie

Are you using the Windows firewall or Norton's? If you're using Norton, disable that piece of garbage and re-enable Windows' firewall. I do a ton of tech stuff on the side anf Norton's firewall couldn't be more of a pain.

Yeah, the PCs use the Norton firewalls. I'll disable these altogether, use the Windows firewalls and see if that sorts the problem. Thanks !