help! h.u. usb port stopped working

[mustangsub 1]

i have a kenwood h.u. that ive had for about 2 years not sure the model name(can get if needed) but it has the 2 preouts in back and usb and aux in the front. I was playing my ipod yesterday and all of a sudden it just stopped , so i unplugged it and tried it again and all it says is reading . i have tried both my ipods and that is not the problem, the aux works fine . any suggestions on how or what i can do to fix it?

[jonbearsmt 919]

did you reset the head unit?

[mustangsub 1]

yes , sorry i didnt put that in the original post. but i did that right after trying both my ipods.