Hello all, im new to the site because this is my first time dealing with androids but im hoping ya'll can help me. I lived in the US for the last few years and now moved back to ukraine and id like to be able to use the phone here, i bought a sim card but it needs a security code? i entered the cards code but it needs another, can ya'll help me out? also another question. i formated mp4 files to fit this phone with a converter but it now makes my computer crash and freeze, can any of you recomend one? I download mp4 files .