Hiding a XP Computer from Network Neighborhood

Getting the File Sharing capabilities to work properly on this player can be a bit of a trick. Unlike a lot of devices out there which support network playback by means of a UPnP (DLNA Compatible) Server, this player uses Windows or SMB (Samba) File sharing.
The player has issues with what microsoft calls "Simple File Sharing", which, unfortunately, is one of the limitations of XP Home and Media Center Edition. The Key difference between "Simple" and "Advanced" File Sharing in Windows, is credentials. When you enable simple file sharing, all clients connect using the "Guest" account. You cannot control access to shares on a per-user basis, if "simple" file sharing is enabled, it's all or no one.
Also, if you have the "Guest" account disabled on your XP machine, your BluRay player will not be able to connect to it using the guest account. If you aren't too concerned about carefully controlling security on your local network and machine, go ahead and try activating the guest account to see if this resolves your issue.
Otherwise, I suggest upgrading to XP Pro, Vista, or 7 - if you want to stay in the Windows World.
Linux is also an option; the Samba packages will allow you to use windows-compatible file and print sharing. I personally run a Linux file server at home, which I access with my BD-P3600. It took a bit of tweaking to get it to work properly though. As I did not want the BDP accessing everything on my file server, I created a special user account specifically for the player, with access only to the folders I want it to access for videos, music, and pictures.
A key thing, which may apply to you, was that I had to manually specify the path to the share. The player did not display shared folders as conveniently as they are displayed within Network Neighborhood in Windows.
The "Automatic Discovery" option didn't work, so I switched it to "manual", or "advanced". The manual method takes you through a series of dialog boxes asking you for the IP of your server, and for login credentials.
Simply enter the IP address of the computer sharing files that you wish to access. If prompted for a username and password, try entering "guest" for both. You could also try creating another account on your computer for the player to use. If you go that route, enter the credentials for that account, if prompted.
Good luck!

This is an excerpt from a MS Technet page for error 53:
Resolutions: 1) if it is domain environment, check your WINS; 2) if it is peer-to-peer workgroup, enable NetBIOS over TCP/IP; 3) make sure the machine is running; 4) make sure file and Printer Share enabled on remote computer; 5) make sure client for ms networks is enabled on local computer; 6) make sure you type the correct name. 7) Make sure no firewall running or any security setting.
Pay close attention to #s 4 and 5 - I suspect XP pro might not be open enough.

I suggest you treat your problem as two separate issues. The first is configuring a Local Area Network (LAN) with file sharing. The second is configuring the wireless communication links.

If possible, set up a "wired" LAN that performs as desired before trying to integrate the wireless links into your LAN. Hopefully you could do this with the desktop computer, one or both of the notebooks, and the wireless router. Does the wireless router have four hard wired LAN ports that function as a switch?

While they don't address the wireless component of your problem, The following Microsoft documents (downloads) are excellent resources for understanding and troubleshooting Windows XP file and printer sharing:
File and Printer Sharing with Microsoft Windows
Troubleshooting File and Printer Sharing in Microsoft Windows XP

There's quite a bit of redundant information, so you may want to start with the second document.

Basically, I'm not a fan of "wizards". When they work, you're very happy. When they don't work, you're very unhappy (and don't have a clue how to proceed). Setup the file sharing manually. The documents above essentially provide a tutorial to do that.

When you cannot see all of the server computers on the network in My Network Places or Network Neighborhood, the solution depends on whether you have successful network connectivity.

To check whether you have basic network connectivity from the browse client to the missing server computer, do the following:

1. Click Start, and then click Run.

2. In Open, type \\ComputerName (in which ComputerName is the name of the missing server computer), and then press ENTER.

If you get a window that displays the shared resources of the missing server computer, then you have basic network connectivity to the missing server computer. If you get an error message stating that the network path was not found, then there is a problem with basic network connectivity to the missing server computer.

If you have successful network connectivity to the missing server computer but you do not see it in the workgroup window, then it could be due to one of the following:

o The missing computers are configured with different workgroup name
o The browse servers do not yet have all the computers in their browse lists
o The missing computers are not on the same physical network segment

Good luck!

you do this by sharing a folder on you win 2k file server computer and setting appropiate permissions
and you access you're share folder via network neighborhood or my network places. you may also may want to map the share folder for you to easily access stuff in it and put stuff back aswell.

you also need some physical set up
your network should be something like this

internet ISP------ modem-------- router-------- file server (win 2k)
-------- your computer
also you neet to give your network a name so all your computers are part of the same network (peer to peer network)

this will give you detail instructions on sharing folders:
http://support.microsoft.com/kb/301281

good luck! let me know how it turns out!