I wonder whether you have "2" tablets installed?
Should be worth checking in Device Manager and even a look in msconfig (Startup) to see what is there.
I still use an "old" wacom serial tablet, which has survived in different boxes and os installations. Though it is not ticked in Startup and is the first thing on the screen, disappearing before the full desktop appears it works fine when I want it. (This is Win98SE by the way.)