Shaky mouse

History: My company builds our own whitebox clones. We are experiencing an ongoing problem in two of our customer locations. Both are schools. The systems at each location are similar, but not identical. At one school there is approximately 80 units and the other has approximately 40, with the same configurations.

The system specs are as follows: Intel D815MB, PIII 933, 256MB PC133, ATI Xpert 2000 Pro, SMC 1211 TX NIC, Toshiba DVD-rom, TEAC floppy, WD200 20GB HD, Windows 98SE, all in an Enlight 7101 super mini.

The problem: A small percentage of these machines have a "nervous mouse" That is to say during normal operation the mouse cursor will vibrate/shake on screen uncontrollably. You can not use the computer at this time. It will generally last 5-10 seconds. It makes no difference what application is in use. When I take a "nervous" machine out of their environment and put it on my test bench it does not have the problem. The main difference in this that I see is the amount of broadcast traffic hitting the machine when it is on their network. The activity light on the NIC is constantly flashing, and in my testing always active during the mouse shaking.

Attempted solutions: I have updated every device driver on the machine. Installed every windows 98 patch/update available. Updated every application on the machine. Updated the mb with the latest bios.

Next attempt: I want to change one of the machines over to Windows 2000 and see if it still has the problem.

Any and all suggestions are welcome.