Windows 7: A problem with network in Win 7

Hi

I have win 7 ultimate x64 installed. everything works well, but I have faced a strange problem! My computer is a member of a network where there are also many computers. However, in the "Network" page, I can see only a few computers!!!
I'm aware of network discovery and firewall settings and these settings are correct on other PCs. As an example, I can access shared folders on a PC in my office by its IP address, even I can connect to this one and full control it remotely from my PC. But this one does not show in the "network" page and I cannot access the computer by its name or connect it remotely.
Although the IP address works fine, since the network is DHCP enabled, this address changes time to time and causes problems for me.
Could anyone please help me what is the problem with my network?
Thank you in advance

What kind of security/antivirus do you have installed on your computers?

Thank you for reply. I have ESET smart security 4 installed. However if I completely disable all security systems, nothing changes and the problem persists

Are you using a third party firewall?

Thank you for your concern. No third party firewall is used. I think if it was a security matter, I could not access other PCs even with IP address, Could I?

Are the inaccessible PCs on the same subnet as the accessible ones?

Thank you Bill2. I'm not sure about the subnet. How could I check this issue?

edit: All PCs are accessible with their IP addresses. The Problem is that only a few PCs are shown on the "Network" page and I cannot access them by their "Computer Name".

Uninstall ESET, don't just disable it, and test your connectivity.

If by page you mean in Windows Explorer view, I have the same issue occuring every now and then. Though I've not found a final solution, restarting Explorer *cleanly* restores the other networked machines. In my case they are not disappearing again for quite long periods, and as I use a custom Jump-List to access most of the items I need regularly, I tend to run into it seldomly.

1. Refresh the Network 'page' in Exlplorer
2. Close all instances of Explorer
3. In Start > Search > type "TSKILL EXPLORER" (without the quotes)
4. Wait for Explorer to reload automatically
5. Hit WIN + E and then click Network
6. Wait patiently without clicking anything

Hopefully you can now see the other machines/devices?

Thank you all friends. Yes OakenG, I mean in Windows Explorer view. I will test the procedure as soon as I access my PC. I also hope it works