While this may be a Microosft issue as my wacom tablet is working fine, my Intellimouse Explorer has started behaving strangely. The mouse pointer sometimes does not respond to moving the mouse, or responds slowly, the light on the mouse goes out for a few seconds at a time, it's not possible to drag some items. I uninstalled the Microsoft mouse software and am just using the osx mouse driver now--same problem.
What can I do to fis this?
If your tablet continues to work, and the mouse is intermittent, AND the light on the mouse goes out sometimes - likely the mouse is failing. If you haven't had it long, you might get a warranty replacement from Microsoft, or just get a new mouse.