You may have gotten a pop up on Windows that says your network resource is no longer available after a password change or password expired notice and while using Network Neighborhood. During troubleshooting you find that others can access share, the server is pingable but you can not access any share on system and it feels like XP thinks the server is not there.
I have found that this was caused by Windows Credentials being stored in the system and that the credentials were not correct. This issue happens in both Windows 7 and XP.
In order to fix something like this you will need to go into the Windows Credential Manager and remove the stored password.
To do this:
Windows 7: Control Panel – Windows Credential Manager
Windows XP – User Accounts – Username – Stored Network Passwords (Top left link)
Once removed retry to access share, you should now see share respond and pop up a user password windows. Place in the correct credentials and you’re in.
I hope this helps someone out there..