What is beeping like accurate time signals in a computer? Not from the speaker ("tweeter"), but from the headphones?

Question

Audio

Computer, Windows 7. Everything was OK. Didn't use sound for a month. Today I connected my ears - the sound is OK + continuously "beeps" as signals of the exact time - about 0.2 seconds peak, 0.8 seconds pause. The mixer shows that these are "system sounds". In the mixer, I strangled the "system sounds", you can use it. But I would like to "solve" globally.
Everything, such as turning off applications and processes, did.
Google asked.
Effect 0.
If there are thoughts, tell me where to dig.

Answer 1

problem with headphones

Answer 2

The problem went away by itself - I usually do not use sound. A couple of weeks later I took the headphones - everything is OK.