Default [Q] Music missing..

Hi,

Appreciate if you guys can help me in this matter.. Everytime after reboot i will lose all the music that already been transferred either to my internal sdcard or externel memory. And that includes all my videos as well. I've tried transferred using htc sync, isyncr and tunesync but everytime i rebooted my phone, all the songs will be missing, as though it was erased. Any help?