I'm running a recent install of Debian 3, and the latest Gnome desktop
2.4 from the apt system. I was running a generic PS/2 mouse, with no
problems until one of the rollers broke. I decided to buy one of the
new optical mice.

I now have a Microsoft Basic Optical Mouse attached to my machine, using
the PS/2 port. The machine is a Hewlett Packard Pentium 200mhz machine.
The mouse works, in almost every way, perfectly.

The one imperfection is an annoying one. Unpredictably, the mouse
cursor will jump to one of the corners of the screen when the mouse is
in use. While I'm typing this, the mouse is stationary, and the cursor
stays where it is. When I start using the mouse, every 30 seconds to a
minute, the cursor will jump to one of the four corners of the screen.
Sometimes it seems to correspond to a refresh of some app, but not always.

The mouse never jumps to any other place than the corners. I've looked
for any setting that might cause it (jump to the OK button on a dialog,
for instance) but cannot find one.

Any help would be appreciated. Email address is protected by clothing.
XFree86Config-4 file is below.