Trouble with input and output sound
 

Ive had the Mbox 2 with Pro Tools LE 6.8.1 for about 2 weeks now. Everything was going smooth until PT does not detect any input sound going through the Mbox2. It doesn't peak when i turn the input knobs all the way up and pat the mics, and the input level bars in the mixing screen never move. I had successfully recorded two of my bands songs that previous week, and when we tried to move on with another song, the Mbox failed to work. When you try to record a track you get nothing, and will hear nothing. I was wondering what could possibly be wrong since it was working earlier.

Thanks