How can i unlock my samsung sch-450 after switching to to nam2?

my friend was messing with my samsung sch-450 and he switched nam1 to nam2 and when that happened the phone just restarted and when it turned off and it just turned back on but then it asked for a code and i tried my pword, my lastest 4 digits to my phone, and 0000 and none of them worked! can someone please help me unlock it!