1. Ensure that the network interface cards (NICs) for all computers are properly secured and that each has the most updated drivers installed.
2. Ensure that the switch or hub that connects the entire network is in good and working condition.
3. Ensure that the NIC led lights flicker when every Ethernet cable is securely and properly plugged in each UTP (unshielded twisted pair) port. Ensure also that each Ethernet cable is in proper working order (end-to-end) and is under the prescribed length limit (under 50 meters). Ensure also that the UTP connectors are prepared for straight-through connections (as opposed to Ethernet crossover cables) – we do not have specifications for using peer-to-peer Ethernet cabling.
4. Ensure that there is a check beside the item File and Printer Sharing for Microsoft Networks in the appropriate Local Area Connection Properties.
5. If the physical layer of the network connection appears to be in good working order, try the following steps exclusive of each other but in the order prescribed below. Items a, b, d, e and h are only applicable on the server PC while items c, f, g and i can be tried on both server and client PCs. Disclaimer: the settings described below aim for maximum sharing operability possible. As a consequence, major security problems may occur if any of the configurations found below have been adopted. It would be wise to reverse all of the adopted policies found below once the project processing phase has come to an end:
   
   1. Add File and Printer Sharing in the Exceptions list of the Windows Firewall (or any other third-part firewall/anti-virus package).
   2. In the properties of the shared folder, add Everyone under the security tab, and Allow Full Control permissions for this user space. Due to the unsecure considerations this step entails, it can only be made safe if implemented in an isolated and trusted environment.
   3. Try synchronizing all Windows usernames and passwords for all computers in the network. The default administrator username is set to administrator.
   4. Run secpol.msc. Under the User Rights Assignment tree node, attempt to realize the following settings:

   Access this computer from the network: (add Everyone to this list)
   Deny access to this computer from the network (remove Everyone and Guest from this list)

   5. Run secpol.msc again. Under Security Options tree node, attempt to realize the following settings:

   Accounts: Limit local account use of blank passwords to console logon only - Disabled
   Network access: Let Everyone permissions apply to anonymous users - Enabled
   Network access: Shares that can be accessed anonymously - add <folder_name> to this list

   6. Install the IPX/SPX/NetBIOS Compatible Transport networking protocol.
   7. Install NetBEUI networking protocol.
   8. Patch TCPIP.SYS using the resource outlined in http://www.lvllord.de/ (officially unsupported, use at your own risk and discretion).
   9. Disable Windows Firewall (or any other third-part firewall/antivirus package). Warning: use this only as a last resort!

This legacy content was taken from an internal article I wrote for my place of work a few years back. I am archiving it here in the hopes that it could help others who are (still) using wired Ethernets on Win XP.