Download a region-free Firmware codes (RPC-1) to patch the existing one inside your region-protected (RPC-2) BTC DVD writer. This firmware modification is considered risky for common users and would took some time to study, understand, and experiment.
This website click here has some information on patching of firmware codes. But I think you still need to use a free companion software tool (DVD Genie) to work with your PowerDVD in order to watch DVD discs from various regions successfully. You can find information on "DVD Genie" in this website click here.
The most easy solution is to use the well-proven "DVD Region-Free" shareware tool to run in the background. It is currently in Ver 3.25 and you can find it in this website click here.
I have recently tried out "DVD Region-Free" Ver 3.22 and it worked flawlessly. For your information, my system's DVD region counter has reached a zero status some time ago but it is no longer an issue now.