Hello, I just plugged my POD HD 500 into my computer to record something...messed around a bit with recording and playback settings then disconnected the USB

Now when I try to play my guitar through the POD HD using headphones, I get no sound...but if i connect it to my comp...i get the sound through my comps speakers? How do i fix this?

just found out that volume knob on my guitar is loose...it can keep spinning without it being locked to "full volume"...does anyone know how to go about fixing this?
Pull the knob off. Sometimes they are screwed in. Other times you just pull. See if the nut for the pot is loose. If so tighten it. Loose pot/jacks are the best way to kill your wiring.

Still not your problem if you have sound from your computer but not headphones.