who used "DVD region free" before ? i cannot make it work

i enabled this software, choosed region to be 1 (USA, canada),
then start PowerDVD, but it says no disk in drive D:.

If i put in a DVD from china, it works.

But the funny thing is, the DVD properity says it's in region 1,
which is for US.

If i change it to region 6, the DVD rom disappears from windows explorer
after reboot.

Anyone knows how to solve this?
The DVD worked before, but i reinstalled my system.