One day your laptop and desktop PCs are happily sharing files, the next day they won’t. We look at several reasons and solutions for this failure to communicate.

By Ron Pacchiano

Q. In my home office I have two PCs: a Windows 2000 workstation and a Windows 98 laptop. These machines are connected to a Linksys router and share a Road Runner cable modem. My laptop is my primary system. I use it at work and while traveling.

I use my desktop computer primarily to store files and print documents. For more than a year, I have been transferring files from my laptop to my desktop via Zip disk, which is really a hassle. Printing is also a problem because I either have to print directly from my desktop PC (after transferring them from my laptop) or temporarily attach the printer to the laptop.

A colleague recently mentioned that I could set up a workgroup that would allow me to move data easily between the systems without using the Zip drive and print from my laptop without having to disconnect anything. So last week he gave me instructions for enabling File and Print Sharing on my PCs. I walked through the steps and what do you know, everything worked perfectly.

This lasted for a couple of weeks. The other day I tried to access the shared drive on my desktop and was unable to connect to it. I couldn’t send any print jobs to the printer either. The desktop PC also cannot see the laptop anymore. I don’t understand what could have happen.

Both systems still have Internet access, so I know I’m still connected. ZoneAlarm is installed on the workstation and I thought that might be the problem, so I tired disabling it, but no change. I have removed the network card from the laptop, reinstalled it and still nothing. I verified that both machines are in the same workgroup and are on the same network segment: 192.168.1.x. At this point I am not sure what else I should do.

Do you have any idea what I might be missing here?

A. This is perplexing, but there are a few things you can try. First, make sure that ZoneAlarm is really disabled. If it isn’t, then you might experience the problem you describe. By default, ZoneAlarm will protect your system from attacks.

This applies to both external and internal attacks. In order to use ZoneAlarm and maintain access to your local network, you’ll need to place your local network in a ZoneAlarm trusted zone. To avoid the issue, you might want to consider uninstalling ZoneAlarm until the problem is identified and resolved.

With ZoneAlarm now disabled on both systems, try to ping the workstation from the laptop. If you get a reply, then you know the machines can communicate with each other. Now try mapping the drive again to the shared folder or drive. If it fails, try mapping a drive to the share using the systems IP address in place of the system name. So for example if the Windows 2000 system had an IP address of 192.168.1.10 and you shared a folder on it called data the map path would be //192.168.1.10/DATA.

If that works, then NetBIOS might have become disabled. So now let’s verify that NetBIOS is enabled on both systems. NetBIOS or Network Basic Input/Output System is a program that allows applications on different computers to communicate within a local area network (LAN).

NetBIOS is used in Ethernet and Token Ring networks and, included as part of NetBIOS Extended User Interface or NetBEUI protocol. NetBIOS frees the application from having to understand the details of the network. A NetBIOS request is provided in the form of a Network Control Block (NCB) which, among other things, specifies a message location and the name of a destination. If NetBIOS somehow became disabled, you wouldn’t be able to see the other devices in your workgroup.

To enable NetBIOS in Windows 2000 open the Control Panel and double-click the Network and Dial-up Connections icon. Right-click the Local Area Connection icon and select Properties. From the dialog box choose Internet Connection (TCP/IP) and press the Properties button. Press Advanced and move to the WINS tab. You should see now see the option for NetBIOS over TCP/IP. Select it and press OK. NetBIOS is now enabled.

The only other thing I can think to try is check that the Computer Browser service is started. The Microsoft Computer Browser service maintains lists of your network’s Windows-based domains, workgroups and computers, as well as other network equipment that supports the NetBIOS protocol (for example, printers, network attached storage (NAS) units and so on).

These lists are the source of the information that users see when they expand Network Neighborhood in Windows Explorer. In Windows 2000 based networks, the Computer Browser service exists only to support earlier Windows versions. In native-mode Windows 2000 Active Directory (AD) networks with AD-enabled clients and replaces the Computer Browser service. However, mixed-mode networks, which maintain pre-Windows 2000 Domain Controllers (DC) and networks with clients that aren’t AD-enabled still use the Computer Browser service.

To enable the service go to the Control Panel and click Administrative Tools and select, Services. Locate Computer Browser in the list, right-click it and select Start. More info on what the Computer Browser service does and how to troubleshoot it can be found in the Microsoft Knowledge Base article Description of the Microsoft Computer Browser Service and Troubleshooting the Microsoft Computer Browser Service.

I hope this resolves your issue. Good Luck!