Users kicked off randomly on WPMS

We’ve set up a large WPMS install for our local school system, and are currently developing the site. There are 150+ sites set up, and it works fine, with one issue.

Some of the users are getting kicked off while working. It can be while working on a page or post. The users are all working in a computer lab, on imaged hardware that is identical in setup, configuration, etc. Here are the details-

– It does not happen to all users, just some randomly, and not always on the same machines. Out of 20 people in the room, 4 or 5 may have a problem.

– Switching machines does not help. The user can switch, and experience the same issue. Another user can get on the same machine, and not have an issue.

– When they are kicked off, one of two things happen:
— In a few instances, the Windows pop-up about the program not responding… “would you like to send an error report”, etc., comes up, and the browser crashes.
— In most instances, the user is simply booted out and returned to the WP login screen, almost as if they had initiated it themselves.

– In all cases, the users are on Windows XP and IE 8

– The WPMS install is on a dedicated server with good specs. We use a similar, separate server to run several hundred websites without any hardware issues.

– The number of users logged in at any given time for the WPMS install is around 25-30. All are Editors.

– We’ve tried deleting their accounts, and setting up new ones, which did not help. We even set up a test site to see if it was a configuration issue with the site itself, and that did not help.

– The behavior is not happening on Chrome or FF. However, because it is a school system, users aren’t always able to install an alternative browser themselves. Also, because they are on XP, my understanding is an upgrade to IE9 is not an option.

So far, this has the look of a browser issue to me, but if there is a way I can help them figure a fix given the confines of the system they are in, I’d like to. And if anyone has experienced this before and knows if it may not be a browser issue, I’d love to know that too.

Thanks for any help in solving this mystery!