Extruder problems and failed to connect to computer

Extruder doesn't push filament through. I can push filament by hand and it flows form nozzle so it's not clogged. But when I try to print extruder isn't pushing any filament through.

Also computer does not see printer when hooking up cable. I've tried three different printer cables and still computer doesn't see the printer. Consequently I can't print directly from my computer.