Cursor "breaks" after sleep

I'm running WinXP on a Thinkpad T21. I have a Kensington USB
ExpertMouse that I use when I'm working at my desk. (Although the
problem occurs regardless of whether I'm using the Kensington.)

Whenever the computer goes to sleep, the mouse stops functioning
properly. The cursor changes to a dot and up/down or left/right arrows
(I believe these are the horizontal/vertical modes) and cannot be moved
away from the edge of the screen.

The only fix seems to be rebooting.

Any suggestions on getting it out of this mode or allowing me to regain
control without rebooting?

Thanks! -Cloy