my 30 GB ipod WAS working fine for about 3 weeks, then my ipod froze so i restarted it, then on screen there was a picture of a folder and a triangle sign w/ an exclamation point, i've had this problem for 3 weeks, but i've was on vacation, what do i do, do i need to return it to best buy for a new one (i have a four year service plan or something close to that, that should be good enough right?)?