||[Monday 12th February 2007 at 8:04 pm]
This is one of the least documented effects of the Windows Firewall, and also one of the most important.
If the Windows Firewall service is disabled, under Windows XP, then the computer will not be able to become a browse master. This in turn means that it will not be able to advertise the workgroup it is a member of.
I do not know how or why the Windows Firewall service affects this. All I know is that it does, and it shouldn't.
I have just spent several hours going round in circles trying to fix this.
(apparently this is a known bug (KB 889320), but you can only get the fix by phoning Microsoft or waiting for XP SP3)