i have trouble starting classic worksheet maple 12.  it used to work fine, but now it freezes at the maple 12 title page.  when closing the program, classic worksheet asks: "You are in the middle of a computation.  Are you sure you want to interrupt it?", even though i have not entered any commands and am unable to enter any commands.  The program also does not close correctly in the task manager.  i have to end the process manually or end the process tree manually.  any help on how to fix this problem?  i have tried uninstalling and re