hit ctrl-alt-del keys simultaneously the click on task manager in the list of applications select winplot and then click end process and it should clear the subroutine and allow you to use the plotter,..you may have to reboot the plotter and put it back online again,..this sort of thing usually happens when one ends the plot process during or before the plot process is completed,..the subroutine is more than likely a proprietary plot spooler