I'm not sure how your motor is going to take inputs from a computer but I would assume it would be via a USB port or some other output connection.
Depending on the size of the motor, it could conceivably get enough power to it via the USB port to drag a piece of paper - otherwise it would need a separate power source and just take signals from the USB connection.
Does this give you some guidance
Communicating Through USB Ports with Visual Basic
I would presume you know your way around electronics so this page might also help you on the hardware side of things
Hobby Servo Tutorial - learn.sparkfun.com
The visual effect of a slide moving off the page and becoming a piece of paper would look great so I hope you find a way to make it happen.