As of a week ago this problem started happening.  3 node network with one system not seeing a networked drive.  2 of the systems show the n/w drive.  All running XP/ 2 w/o any SP's  / the one with all the updates is the one not seeing the drive.

N/W drive is a Buffalo Linkstation HD-HG400LAN / checked their support site and they recommended enabling NETBIOS over TCP/IP / didn't work on the pc in question / tried it on my LAPTOP and it worked. 

System has Norton AV 2009  / tried Safe Mode with same results.

Alan <><  In what sense can you not see the drive, Alan?  Can you ping it?  Can you ACCESS the web interface?In what sense can you not see the drive?  It is not SEEN in My Network Places\Explorer.  I can map a drive LETTER to a folder on the drive, just not see the whole drive in the one computer.

Can you ping it?  Yes.

Can you access the web interface?  Yes.  Thru the software on the computer in question I can login to the drive interface with no problem.

Alan <><  If you browse from Windows Explorer's ADDRESS bar via IP address rather than NetBIOS name (e.g. "\\192.168.1.100"), can you see all the shares?  If so, I suspect that you have a firewall issue on the one computer that can't see the drive.  Make sure that the following ports are all open: 137, 138, 139 & 1512 (tcp & udp).Thanks Rob.  I did shut off the firewall but will double-check it next week.

Have a great weekend 

Alan <><