Silent PCs are rarely broken - something in the audio chain is pointed the wrong way: the wrong output device, a muted app, a stopped service or a failed driver. Instead of trying fixes at random, walk this checklist from top to bottom; each step takes a minute and rules out one link of the chain.
Quick answer
Click the speaker icon in the taskbar and check the output device first - after connecting a monitor or TV, Windows often switches sound to its HDMI output. Pick your speakers or headphones, then check volume. That single step solves a large share of "no sound" cases.
HDMI monitors, TVs and USB devices register as audio outputs and silently become the default.
Windows keeps per-app volume - one accidental mute in the mixer silences just that app, which looks like a mystery.
After updates, the audio driver may be swapped for a generic one or stop working - the device disappears from the output list.
Windows Audio and its endpoint service occasionally hang; every device then shows as unavailable.
services.msc and press Enter.If you do not know the exact model, several devices need attention at once, or the manual route did not find a match - Outbyte Driver Updater identifies your installed hardware automatically and updates the drivers from official sources, with a backup before every change. The scan and diagnosis are free.
Download Driver Updater Downloads Outbyte Driver Updater for Windows 11, 10, 8 and 7. Free 2-day trial, no credit card required.The monitor registered as an HDMI audio device and Windows switched the default output to it. Select your speakers in the output list (method 1) - and Windows remembers the choice per device combination.
A per-app mute or a per-app output device: open the Volume mixer (method 2), unmute the browser and check its output device. Also check the mute button on the browser tab itself.
The driver layer: a generic or failed audio driver keeps devices off the list or silently broken. Reinstall it properly - the Realtek guide walks through roll back, clean reinstall and the right download source.