What you have is called a Home Theater in a box. The karaoke is part of the DVD player part only so you can't use your laptop with it. To use your laptop and a mic you will need an mic line mixer that will combine the music from the laptop and the vocal from the mic and feed it into the Aux1 on the HTIB. A cheap DJ mixer should work. Make sure it has RCA outputs that will connect without an adaptor.