Problem accessing workgroup computers?

[Doohickey]

Hey

I seem to be having trouble accessing a workgroup computer on our LAN, when I try, it tells me that

\\xxxx is not accessible. You might not have permission to use this network resource. Contact the admin... etc, The network path was not found.

I can't see what I need to do to enable this, NetBIOS over TCP/IP is enabled on both machines, as is the Computer Browser service, and no firewalls are up.
Help!

 

[hybrid]

Can you access the machine by IP?

Can you ping it? By IP and Hostname?

Are they both within the same domain/workgroup?

Are they both in the same subnet?

Can you see them in Network Places/Network Neighbourhood?

If XP, have you turned off simple file sharing?