Netbios broadcast not working

If the firewall on that machine is blocking the 3 ports you need for a netbios LAN you shouldn't be able to connect to it at all...  but here's how to check that Windows Firewall is allowing it...
Start->Run, NCPA.CPL [Enter], then click 'Change Windows Firewall settings' in the Network Tasks menu on the left side, ensure Don't allow exceptions is NOT checked on the General tab, then on the Exceptions tab, File and Printer Sharing should be checked.

How are these computers getting their IP addresses?

I assume you've checked that the Computer Browser service is running on all of them?

What all OS's are involved?  (mainly wondering why the win9x networking zone is in the list, but checking for vista too).

ChiefIT's description sounds just like the behavior I'm seeing but the firewall is and has always been OFF.  Computer browser Service is running as well. I restarted it just to see if that made any difference.  It did not.  Also have notification of any blocked ports checked even though Firewall is off just to see if there are any messages when somethings blocked.  There aren't.  I have AVG 9.x running but it's not set to be firewall (that I can tell).   File and Printer sharing is included in list of Exceptions for Windows firewall although that shouldn't matter since Firewall is off.  I can browses the file shares if I access them via WinExplorer by \\computername\sharename. All machines are WinXP with all updates installed.   One machine is Linux running as DNS server and File Server but it just sits in corner and I leave it alone.   That's the way the machines get their DNS address.   I've been running this machine for several years with no issue.   The problem with this one machine is new when I added machine to network.  There are NO Win98 machines on network - I made a mistake when I posted this question by including that zone (Would remove it if I knew how).  I don't know if it's related or not, but another symptom (?) is that this for this particular machine, I cannot RDP into it without being bumped off by it's administor after about 3-5 minutes even though I'm RDP'ing in as administrator.   All settings and RDP users are appropriately authorized but it's as if the machine sees an RDP user, finds it's not authorized and disconnects with associated message.   If this isn't related problem, I'll post as another issue I need to resolve after find solution to this "invisible computer" problem.   I appreciate both of your suggestions but I'm still puzzeled.

Routing and Remote Access Services (RRAS), will enable Windows firewall even if Windows firewall is disabled in Services. Do you have RRAS enabled on the trouble child machine, or do you have it multihomed, (meaning two nics or two IP addresses for the same machine).

Is samba running on the linux box?
If so, tell it to be your WINS server too, and replicate the LMHOSTS file for your workgroup in samba.

How the workgroup machines find out about the WINS server depends on how your computers get their IP addresses, which you apparently missed in my previous post... are they static IPs?  Do they get them from a DHCP server?

ChiefIT - Routing and Remote Access Services (RRAS) is not running (Disabled) on the problem machine.  There is only one NIC and one IP address for this machine.

Darr247 - Samba is running on the linux box.   I'm not really a Linux literate person but I know that WINS is not running on that machine.   I don't know how to enable it since someone else set this DNS and DHCP server up for me a long time ago and my interactions with it have been pretty basic as a Linux user. This was all a couple years before this problem occurred on this particular (new to the Workgroup) machine.   I don't mess with this Linux/Samba/DHCP/DNS server because it has run so flawlessly.   All IP addresses for WinXP machines on network are obtained thru this DHCP server including the problem machine.

Thank you both for your help and suggestions.

At this point, we should look in event logs to see if there is a browser conflict between two machines.

Browser elections are done by the highest operating system (with holder of FSMO roles) within the domain. You are on a workgroup, So, you will not have a FSMO role holder. In this case, the highest operating system wins the election.

If there is a browser conflict, you will see in event logs, Event IDs in the 8000's. Examples are 8003, 80032, and 8021. These will tell you something like:

"xxxcomputer thinks it is the domain master browser, the browser service has stopped and an election has been forced"

First off, you should note that Netbios and DNS are two separate entities. Netbios is used for the browselist. The browselist is used to populate a list of shares and comptuers in "My Network Places". We are NOT troubleshooting DNS. We are troubleshooting Netbios.

A few command line utilities can be used to troubleshoot Netbios and the Browser services.

One is called NBTSTAT

The second is called BROWSTAT

A third is called NET CONFIG.

A fourth is IPconfig /all:

NBTSAT will allow you to look at an manipulate the Netbios cache, (also commonly referred to as WINS cache).
--The syntax can be seen by going to the command prompt and typing NBTSTAT -?

Browstat, will allow for you to see who your master browser and backup browsers are.
--The syntax will be Browstat /status

NETCONFIG will show you the NIC conifguration, specifically the redirector. The redirector shows you what netbios is bound to:
--The syntax at the command prompt is Net Config redir

IPconfig /all will show you how your NICS are set up>

You will see NODE TYPE (which is a netbios feature), and also if Netbios is enabled.
--If netbios is not enabled, you must have File and Print sharing, as a binding. Then, you must also have Netbios over TCP/IP enbabled on the NIC Configuration>>WINS tab.

There are no 8xxx EventID's nor any messages like the one you noted.   I can find the NET, IPCONFIG, and NBTSTAT commands, but BROWSTAT is not recognized as internal or external command.  I'm not sure how to interpret the output from the commands you listed.  One thing (odd?) is that on output from ipconfig /all command indicates that "node type" is "unknown".  Host Name is correct as is the Primary DNS Suffix and the IP address.   I can capture and post  output from any of these commands (except BROWSTAT) if that would be helpful for you to examine.   Thanks again for helping.

Browstat is a member of the 2003 server support tools and can be downloaded.

It is compatible with XP operating systems.

One indicator that would help is what do you see in "My network places". Netbios broadcasts are used to elect a master browser. The master browser is responsible for populating a list of computers in my network places.

In your situation, It does sound like WINDOWS FIREWALL> the reason I have that in bold is because windows firewall will re-enable itself upon some service pack updates. So, that could be the problem. Another common problem is Netbios will bind to one adapter and not the other. So, if you have two nics on this, it could cause this issue. I swear I have seen this before and Windows Firewall was the culprite. If Windows firewall is disabled, renable it and disable it again.

Sorry for the long delay.  Between my day job and all the things ChiefIT suggested I try, it took me till this weekend to experiment with suggestions and identify the culprit that seems to have fixed this problem.   It's a long story but the net of it is that I had installed a utility from DynDNS.org that periodically checks external ('non-sticky') IP address assigned to my router by my ISP.   When it notices the IP address changes for any reason, it updates the settings at DynDNS.org such that my xxxx.homeip.net external URL will refer back to my router's new address.  I have this URL registered at DynDNS so that it will refer specific access to this URL to my router from outside my home network.  I rely on this when I'm away from home and need to access router on my home network thru special ports for various applications I use.   (Yes, I know this can be risky, but the router has a limited number of strange ports open, so....).    After not finding any other explanation for my problem, I started examining all the running services and noticed the utility relied on two service one of which was not started and other other of which was set to Automaticakky start.   When I disabled that service the Netbios name of this particular computer (which is the one that the service runs on) showed up again and stayed visible.   As soon as restarted the DynDSN service, it disappeared.   Apparently, the service forces it's own DNS server addresses into the network connection that and somehow that affects netbios (?).  Or at least that's my hypothesis.   I'm not sure I completely understand what this service is doing to make netbios disappear with these symptoms but I'm sure that disabling it makes everything work as it should.   I'm going to research this more at the DynDNS website looking for explanation because I really want the utility of having something that checks my external ISP IP address and updates it whenever my ISP changes it.   I wanted to post this information without further delay so that it would appear as though I had abandoned this question.  If I discover explanation for this at DynDNS, I will post explanation.   Meanwhile that seems to have fixed my problem.  I'm open to suggestions as to what might be going on here.   Now I only have the matter of not being able to RDP into this particular machine to troubleshoot but I'm convinced that's a different problem.   I'll post a new thread for that when I can get to it.  Thanks for the help.

Here's a similar question I can't make heads or tails on.

http://dyndnscommunity.com/forum/viewtopic.php?f=36&t=2605

Why in the heck would DynDNS have anything to do with Netbios translation. It makes no sense to me.

However, I could see it causing your RDP problems.