Problem with shared resources.

2 PCs in one office.  Both connected to my company's VPN, both joined to my company's domain.  They don't log onto the domain, however, only to the local drive.  When domain resources are requested, they're prompted for domain logins.

Both machines running Win XP, SP3.

PC 1 was having a connectivity problem.  It was specific to the machine - PC 2 was connecting to the internet with no problems.  I ended up installing an ethernet card in PC 1, at which point the internet connectivity is working fine.

The problem is that there are shared documents on PC 1 that PC 2 is no longer able to connect to.  

Get message "PC 1 is not available.  You might not have permission to use this network resource.  Contact the administrator of this server to find out if you have access permissions.  
There are currently no logon servers available to service the logon request."

I have enabled File & Printer Sharing on the new Local Area Connection for the new ethernet card.

I disabled Local Area Connection 1.  Repaired the network connection on each, rebooted the common router.  

I also turned off Windows Firewall on both machines; no change.

Able to ping PC 1 from PC 2 using PC 1's IP, but not its computer name.  Which indicates to me a DNS problem.  When I go to Network Places on PC 2, PC 1 is showing there, but it won't let me click into it, or right-click to see PC 1's properties.

I'm sure this is something I'm just overlooking, but I'm not sure what, and in the meantime, their PC 2 is relatively useless without being able to use the Shared docs they need.

Any help would be appreciated.

Thanks.