Let's say you connect 2 computers, running any of the many versions and editions of Windows, with default configurations, in a network. To find each computer from the other, you open Windows Explorer (don't confuse this with Internet Explorer, please), and look in My Network Places (aka Network Neighborhood). On a fully working LAN, this will work just fine. In your case, it may not.
In your case, Computer A shows both Computers A and B, as it should, and files on Computer B are accessible. On Computer B, either you don't see Computer A, or when you try to access Computer A, you get an error. You may, or it may not, see Computer B. This visibility problem may be observed constantly, or it may come and go.
This visibility problem is possible on LANs with Windows 2000, Windows XP, and / or Windows Vista, in any combination.
Now before you start, you should be aware that you will enjoy this more, and frequently will be more successful, when you work on a properly designed and setup network. After you review that tutorial, I recommend that you tackle the task at hand in this order.
- Check for a personal firewall problem. A misconfigured or malfunctioning personal firewall, on either computer, can block browser access. Do you have antivirus protection? Make sure that your antivirus is not part of a package that contains a personal firewall, and does not contain a component that acts as a firewall.
- Look carefully for a hardware firewall, sitting inside your computer. The nVidia nForce is probably the first, but surely not the last, device of this type.
- Some newer, WiFi routers, have a complete firewall between ALL client computers, connected wired or wireless. Look for an "Isolation Mode" setting, if no computers are visible to each other. Each vendor uses a different name for this feature, so read your user guide carefully, if you suspect that this is a problem.
- Make sure that NetBIOS Over TCP is consistently set, in TCP/IP Properties for each computer in your network.
- Does your LAN include any computers running Windows Vista? If so, be aware of the additional issues involved in Windows Vista and Windows Networking.
- Do you have a share setup on each computer? With Windows XP / Vista, only computers with non-administrative shares (not ending in "$") will be visible in My Network Places (aka Network Neighborhood).
- Make sure that all computers are in the same workgroup, if you expect to see them in the root of Network Neighborhood (My Network Places).
- Check for several well known and lesser known registry settings, which will affect visibility of, and access to, your server.
- Look at the content of the error message. Do you see either "error = 5" (aka "access denied"), or "error = 53" (aka "name not found")? Read the appropriate article, and follow the links.
- Look again at the complete and exact text in any observed error messages. Some very obscure errors have very simple resolutions.
- Run, and examine output from, "browstat status", "ipconfig /all", and "net config server" and "net config workstation", for each computer.
- Post output from the above step for expert interpretation and advice. Include relevant background details in your post. When including diagnostic logs, such as "browstat status", "ipconfig /all", or background details, format them properly when you post them.
- Make any changes in your network per the advice of the helpers in the forums. Retest as advised.
- Run, and examine, CDiag output for each computer. If you have more than 3 computers, post diagnostics for at least 3, and try and include some computers which show no symptoms of the problem (if any exist), as a control. The more data here the better.
- Post output from the above step for expert interpretation and advice. Again, format CDiag logs properly when you post them.
- Check that all necessary network components and services are provided. The necessary protocols and transports must be loaded and activated. The necessary services should be Started and Automatic.
- Run, and examine, CPSServ output for each computer. Try and do this on the same computers that you ran CDiag (above) on, to make the diagnostics more effective.
- Post output from the above step for expert interpretation and advice. Again, format CPSServ logs properly when you post them.
- Check for, and remove, unnecessary protocols and transports, like IPV6, IPX/SPX, and NetBEUI. Unnecessary protocols and transports can block Server Message Blocks, and cause problems. Check "browstat status" logs for evidence of IPX/SPX or NetBEUI. Check "ipconfig /all" logs for evidence of IPV6. Remove any protocols found. If you solve your immediate problems, you can re in stall any protocols removed, later.
- Check for LSP / Winsock / TCP/IP corruption. The LSP / Winsock layer in the network, on either computer, can malfunction, and drop SMBs. If you have more than 2 computers, the computer causing your problems may not be immediately apparent. Use CDiag to identify the computers to work on first.
- Learn how to solve network problems.
- Try my comprehensive troubleshooting guide, Troubleshooting Network Neighborhood Problems. Use CDiag and / or CPSServ logs, to identify the computers to work on first.
- Read about The NT Browser and Windows Networking.
- Read about File Sharing Under Windows XP.
NOTE: The comprehensive troubleshooting guides, referenced in Advanced Diagnostics, contain all of the other sections and more, sequenced by network design (ie, physical connectivity issues first, and file sharing permissioning last). The last article talks about problems specific to File Sharing, such as authentication and authorisation, and it is most useful when all other problems (such as are discussed in the previous step) are resolved. This article, as a whole, emphasises the most productive procedures for resolving your symptoms. You are free to try any of the above steps, in any order which pleases you - it is, after all, your network.
These are simply the procedures which currently seem to produce the best results. So become familiar with them, because, if you ask for help and I am involved, I will likely ask you for the diagnostics discussed above. And, if we don't get immediate results here or elsewhere, I'll ask you to repeat each step above, one by one, as I examine the results. Read each linked article, and follow the links within each article.
Now I'm a Networking and Security advisor, and I don't provide advice on security issues casually. Using the Internet, without considering the privacy and security implications, makes trouble for a lot of innocent people. When you're considering the necessity of providing requested details about your computer network, in an open Internet forum, please read this brief Privacy Statement. Help us to help you.