The printer worked for years and suddenly the computer cannot see it. You changed nothing. This is the order I go through it in.
1. Does it print anything at all on its own?
Most printers can produce a test page without a computer, usually by holding a button on their panel. If it cannot manage that, the problem is in the printer itself and has nothing to do with the computer — it is out of toner, has a paper jam, or is reporting an error.
2. Is it on the same network as the computer?
This is the most common cause with wireless printers. Modern routers broadcast two networks — one with 5G or 5GHz in the name and one without. Printers can often only use the slower one without the suffix.
When your computer or phone switches to the other network, the two stop seeing each other. Check which network you are connected to and, if necessary, switch to the one the printer is on.
3. Restart both, in the right order
Switch the printer off with its button and unplug it. Restart the router. Wait for the router to come up. Only then plug the printer back in and switch it on. Finally, restart the computer.
The order is not arbitrary — the printer takes an address from the router as it starts, so the router has to be running first.
4. Check the print queue
In Windows, type Printers & scanners into search, click your printer and open the queue. If old documents are stuck there with an error, new ones line up behind them and never print. Cancel everything and try printing again.
Sometimes a printer picks up a setting called Use printer offline. That has to be off.
When several printers with the same name appear
It happens that Windows lists the same printer three times, with suffixes like “(copy 1)”. You then print to one that does not exist. Delete them all and add one back.
When it is time to call
If you have been through all of it and the printer still does not respond, it is usually the drivers — particularly after a larger Windows update. Reinstalling the driver can be done remotely and is usually a quarter of an hour's work.
What I would not do: download a driver from the first search result. Sites promising “free drivers” are full of programs that have no business being there. A driver should come from the manufacturer's site and nowhere else.