Help the new guy

Hello everyone I am new to forums and new to using mbox so please be patient with me.

I need help starting up

I have a korg pa50sd midi in/out to mbox in/out. usb to laptop I am recording fine notes etc clearly visible but when I playback....nothing.

Its really frustrating me.

I have tried everything.

My keyboard amp etc are in fine working order.

What am I doing wrong???

Thanks Andy