When your computer is booting (the first text screen just after you turn the power on), get to BIOS setup by hitting, depending on BIOS manufacturer, either Del or F1 key. Then, go to either Integrated Periveral or Advanced Chipset options or something like that (again, different BIOS manufacturers call it differently) and make sure that the parallel port is enebled. Then try changing the parallel port type--there should be 2 or 3 choices, something like EPP or ESP or EPP+ESP or something like that. I believe that RealFlight's parallel port interface needs some particular parallel port mode, just don't remember which one.