Laptop doesn't recognize when I put in headphones, only plays music through speakers.

Hello. Test the audio driver to find out if the driver is causing the problem, by switching between the Realtek audio driver and the Windows native audio driver. You have to have a Realtek driver installed to use this test.

1. Open the Device Manager (find it in the Control Panel, or type devmgmt.msc into the search box).
2. Expand the "Sound, video & game controllers" and right click on "Realtek High Definition Audio".
3. Select to "Update Driver Software".
4. Click on "Browse my computer for driver software".
5. Click "Let me pick from a list of drivers on my computer".
6. Put a check in the box "Show compatible hardware" if not already checked.
7. In the list of devices, click "High Definition Audio" (the native driver).
8. Click "Next".
9. On the Update Driver Warning box, click "Yes" (install the driver).
10. Restart the laptop if prompted. If not prompted, you might not need to restart.
[To get back to the Realtek driver, do it again but reverse the names in steps 2 and 7.]

If you only have the symptoms with one of the drivers, then the other is at fault. If you have the same symptoms with both audio drivers, then it is very probably not a driver issue.  It could be in the hardware -- either the laptop or the headphones.

This was a known issue with the Inspiron 15R 5521 model when the Realtek 6.0.1.6788 driver was installed. That driver was for Windows 7 & 8. The solution was to install the previous version, 6.0.1.6690. If you think your headphone issue is caused by the driver, you could try installing the 6.0.1.6690 version, using Win7 compatibility mode.