Your dvd drive should be now set to the last region you switched to. Therw are 2 ways around this.
1)
flash your drive to a region free (or rpc1) bios and use a program such as dvd genie. Use
this site to see if there is a region free bios for your drive
2)
you can get something like
DVD region free which will allow you to make any rpc2 (region locked) drive as a region free one without flashing the bios. NB this will only work in windows.
g