No sound coming from headphones, but speakers work fine.

Hello,
I have recently installed windows 7 Ultimate again, and I have been trying to get the sound drivers to work with headphones which hasn't been working. When I plug the headphones in, the speakers play the sound instead of the headphones.

I have tried checking playback devices, no disabled or disconnected devices showed, only the one that says "Speaker/Headphones" which is set as default. The sound driver I have is 'Realtek High Definition Audio' as it is listed in Device Manager, and it has the latest update. I know the headphones work fine (Tried on another computer, and iPhone), and that I hear a slight static of sound when plugging the headphones into the computer jack, with no notification popup saying that I plugged them in.

My computer is Dell Inspiron 15 3521. I have tried downloading the drivers from the support page for my system, but I still get this issue. I know the sound card works fine, as does the headphone jack, so this is a driver issue and I am not sure how to resolve it.