I have an application (CutRite) on a PC that optimizes cut patterns and then
sent to each of the 3 saws. This is done over the COM1 line using an A-B-C
switch to switch between saws.  The distance out to the saws is around 100
yards plus.

Whatever PC I place at that workstation, its operating system gets slowly
degraded over time. I replaced the PC that was there and reloaded the
original PC from the recovery disks and never had a problem with it since.

There are different theories ... one is that the application itself, which
is DOS-based, is the culprit. The other is that we are somehow getting
feedback from the saws into the computer. We have looked at grounding (one
of them was not at one time) and the saw operators now turn the saws off
when they go on break to allow the static electricity to settle down, and
that seems to have helped some.

Any experience out there with issues like this?