One system on network has lag accessing server shares

Hi all, exellent group and a great resource. Here's my problem:

I have 4 systems:
File Server: XP pro SP2 file server. Has 3 hard drives all setup for
sharing the root drive with the following computers
Workstation: XP Pro SP2
Laptop1: XP Pro SP2
Laptop 2: XP Pro SP2
simple file sharing is off. All shares have permission and security
set for 2 admin users, admins, owner and system to have full access.
The "everyone" group is always removed.

All the computers EXCEPT THE WORKSTATION can access the shares
without
any problem. The workstation however, has a lag time when accessing
most folders on any server share across the network. It also lags
when accessing shares on the other laptops as well.

All other system can access all shares without the lag.

I've have tried many things to solve the problem and I am about to
just give up and reformat...unless you guys have idea on how I can
track the cause of the lag. Are there any diagnostics that can
pinpoint this? I can post a list of everythign I've tried.

Thanks in advacne for any suggestions.