PAL/NTSC DVD player help?

My dad recently bought an Apex home theatre system from a man in my area for $500. The DVD player turned out to be NTSC and would not play original PAL DVDs. Is there any way to make the DVD player play PAL DVDs? We called a repairmen and he mentioned some kind of code, but he wouldn't give it to us unless we paid him. Can anyone help help us?