You need to do a little more troubleshooting.
First - take an overall view and see if there is anything that ties the problem computers together: operating system version; available disk space; LAN connections (same hub?); etc. Is is always at the same time of the day? Do you have a program on the system running at that time that may slow down the system and give time-out errors? Is it early in the morning and a virus scan is running in background or a script file is locking them out?
Second - you will need to see what is running when the desktops lock up. Use the old "ctrl-alt-del" and see if it tells you what is not responding. You will have to work closely with the users in trying to resolve this as they have to notify you and then wait until you can do the trobleshooting.
Third - you need to understand what the Access program is doing. Is it downloading complete copies of the database to each station? Is it having problems with file lock/record lock when more than one station is trying to access it at one time?.
Forth - looking back, what happened to the system just before you noticed the problem? Go back through your logs and see if you or someone else modified the system or their computers. Something simple like they all started using an internet screen saver?
On the Novell side do a dsrepair to verify that all is good there. Check your console log to see if there are any problems. If you have a managed system take a look at throughput and lookfor errors.
If there is no immediate answers you might want to reload Access on one of the desktops and see if that fixes the problem.
