Computer doesn t recognize headphones?

laptops & desk tops usually have rinkydibky 1/8 stereo plugs that wear out,ditto the shittywitty crappywappy mousewhisker ear buds with thin wires that break,or lose connectivity in one side,

whether you spend ten bucks at walgreens or 400 bucks for dr dre beats with he pretty red plastic,your machine hardware icon off settings menu ,turn the unit off,wait 5 min,turn it on,go to settings,click hardware new device to plug in,it will instruct you to plug your doodad in,it will say ok,click. done,exit shut the thing off,restart,load,then try an audio track

If you have a video card that has HDMI out for video and sound, then maybe the default audio setting goes out that video port instead of through the motherboard, through the audio chipset, and out any audio socket to the headphones.

The (standard) 3.5mm jacks will wear over time, to where even new headphones may not make proper contact.

Plugging and unplugging any electrical jack wears down the receiving (input) contact, begins to wear down, requiring a little twist/turn to connect, and with intermittent static.

Trying a new, inexpensive set would be my first test.

Oh, and the external laptop speakers working just proves that the sound card IS working.

get new headphones

Probably have'nt met before.