SET UP GUIDE

My AX-M138 DVD/DAB micro hifi system will no longer play Dvd`s, I keep getting error reading " Wrong Region " I remember when I originally set up the system it had a list of regions and I changed it from all regoins to Regoin 2 Europe i.e GB. But I can`t find the instructions and can`t remember how you get to the region selection page. Would be extremely grateful if you tell me how to do this. Have looked for user guide, instructions on Hitachi web site but cannot find anything to help.