>*Changed out network card in the workstation (packets between workstation and server were much slower than other workstations . .. changing card seemed to improve transmission speed.)

Here are some ideas.

1) Check to ensure that the network client is setup identically on all pcs (one thing is to ensure is that only the network protocols that are needed are loaded on the pc).

2) Swap the network drop between a working pc and one with trouble (this may involve swapping the locations of the two pcs)

3) Swap the ports that each computer uses on the network hub.

4) Swap network cards between a working and non working pc

5) If this fails copy the disk of a working pc (with similar hardware config) using a utitlity like ghost (http://www.ghost.com/) Then modify the setup to give the workstation a unique ip address and name and such.