Fair enough, but having to use an obsolete OS and being unable to run your program on a 64-bit platform (without a virtual DOS box) are high prices to pay IMHO. I recommend re-writing the program in a Windows BASIC (of course I'm prejudiced and would suggest BBC BASIC - there's even an automated QBASIC to BBC BASIC translator that will do most of the work). That would give you all the benefits you mention but with a modern OS and GUI.
Richard.
The semiconductor design team I worked in started me with Visual Basic and only switched to QB so we could run our application boards on any customer's unmodified lab PC, off its printer port. In the late 90's hand-me-down office PCs weren't guaranteed to have USB ports but they still all had LPT1, plus the engineers liked using it for its simplicity. For instance it was trivial to make a full-featured I2C interface with it, one pair of control and status bits for Clock and another for Data, and the target's address asserted on the data bus.
I got good enough at QB graphics to draw the IC's layout on screen with the control bits we sent to it running around through shift registers to their intended locations. It looked like a video game battle of colored centipedes, and visually matched with test point locations seen through the microscope on a wafer prober.
The ICs were hot-swap controllers, Power-Over-Ethernet hubs, etc. sold by Texas Instruments.
jsw