how to - unlock password mmc

‘it happend to me, i’ve put password on it & forgot about it, later I found out it was locked due to unplugging battery, I was busting my head how will I unlock it and it happen accidently that I try to open Recorder & then it ask me to put a password, but what happens is that mobile gets an error and when you turn it of & on again it stays unlocked . Lowdown is that after some time it gets locked by it self again. PROWEN