2nd Parrallel Port for laptop

Hello,
Does anyone know how I can add another port to a Compaq laptop?
I was trying the demo version of Mach2 and every thing was working ok,
then my X+ limit switch started acting up. Everything seems to be
working with the exception of pin 11. That was the pin for X+ limit
switch. All other pins seem to be working but I can?t get the motors
to run as smooth as they were. Any help or suggestions would be
greatly appreciated.
Regards,
Don