Hi
First make sure that your cables are good commercial made cables.
Check the Network cards on the computers and make sure that they are Not set
to half Duplex.
Make sure the Network card's drivers are updated
If you have Internet connection optimize the TCP/IP stack for the type of
connection, it would help with local transfer too.
You can use he free TCP Optimizer, http://www.speedguide.net/downloads.php
Check this too, http://support.microsoft.com/kb/932170
If it still slow disable temp 3rd party (if you have one) AntiVirus and or
Firewall and see if it make a difference.
Jack (MS, MVP-Networking)