Today when I came into the office, no one was able to connect to our server. The problem is that when everyone left last night we had no problem whatsoever. The only event that took place between closing and opening the office, was that my GM remote desktopped the server (he has a laptop running XP). When I arrived this morning to look at the server there where errors generated by the Remote Access Wizard. The only person in the office who was able to connect to the server was a temp. She is able to connect to the server through the wireless router (connected to a linksys NIC). I unplugged the LAN cables of a few employees from our 24 port hub (connected to on board LAN), and problem solved...sort of. We still have 12 computers that still can't access the server. I can ping the server, but I cannot access the mapped network drive and the server has disappeared from network places.

Here is what we are running:
Small Business Server 2003
Client PC's consist of everything from windows 98 to Vista

One thing I did notice was that I can connect a few PC's to the server throught the linksys wireless router, if it is plugged into the linksys NIC card. No other combination results in a connection the the server. Help, I am totally fried.

What antivirus are you running on the server? Do you have any sort of firewall on the server?

Some AV/firewall software has intrusion prevention features that will block computers that it deems as bad clients. I've run into this with Symantec Endpoint Protection. Its Network Threat Protection tool by default will block other systems that are not running Endpoint. It could also be the clients that are blocking the server.

Could you give a little bit better description of your network layout? What exactly is between the server's network card and the clients network cards. Like server goes to (make/model) switch which goes to (make/model) switch which goes to client computers.

Antivirus - AVG
Firewall - Hardware Cisco IAD2431

Windows firewall is turned off on all connections.

Network layout:
Server is connected to Zonet ZFS3024 switch (through the on board broadcom NetXtreme 5721 NIC) witch goes to all other computers. We currently have 3 computers connected to a linksys WRT54G wireless router (via ethernet) which is connected to the linksys NIC card on the server. The only three computers that can access the mapped drive and see the server on the network are the three connected through the Linksys wireless router.

I got it taken care of. Turns out it was a pretty simple fix that I should have caught. All I needed to do was reinstall the broadcom driver. The Remote Access Wizard error completely threw me off.