Headphones are not recognised in my playback devices

I was watching a TV show in my headphones, plugged it out for about an hour, plugged it back in during which time my Dell Inspiron 15 would have gone to sleep about 4 times.. I plug it back in after an hour and the music plays through the speakers and I looked up all solutions. None of them work. Checked my audio drives, disabled the speakers and enabled them back.. Dunno what to do. I really hope you guys can help. Reply ASAP, freaking out as it is just a week old, my laptop.