Do not keep that. I can think of no reason that would happen other than a hardware problem.

FYI, I do IT support for a living.

It's not brand-spanking new -- I got it mail-order directly from Lenovo in November last year.

ETA: As soon as I'm back home, I'm going to boot from a Linux USB stick. If that has the problem too, I will send it in.

had to buy an external keyboard for it

I see the post from another person with the same issue. I have not dealt with IBM/Lenovo support in a while. We use mostly Dell at work.

Here is what is most likely going to happen. You HAVE to persevere and get a replacement though.

First, and to save yourself grief (because the Lenovo support will require you to do all this first before they believe there is a hardware issue). Make sure all the Windows updates are current on the machine. Do this by clicking on the Windows start button, then the gear to get into setup and then Update and Security->Check for Updates. Get all those installed. If there is some sort of Lenovo support assistant software on the machine use that to make sure all the drivers and the BIOS are up to date. If there is no obvious support software on the machine go to support.lenovo.com in your web browser. Find your machine and run any diagnostics/updates you can. If you do this you will save yourself a lot of time dealing with the support people on the phone. Also, if there is chat support I suggest you try that. Companies are using chat more than phone support and I've had better response time with chat lately.

1. You have to call tech support and deal with them. Not fun.
2. Stay on the phone and be firm but polite.
3. They will ask you to go through diagnostics to determine the issue. The poor people on the phone with you HAVE to make you do this. Please understand they are not trying to be jerks. They just have to make sure they check all the little boxes in their system so they get to keep their jobs. No matter how stupid the task, just do it (or fake it if you can).
4. Again, I don't see any reason why software or the OS install would be the cause of the issue you are having. If the keyboard driver was corrupt you'd have more going wrong than what you've described.

Good luck.

Much appreciated. I'm still holding out hope it's a software issue, but it doesn't seem that likely.

You say it’s new-ish. Maybe it was refurbished

https://www.drivethelife.com/windows-10/lenovo-laptop-keyboard-not-working-windows-10.html

Your Lenovo laptop keyboard is not working in Windows 10? Don't be frustrated. Here are top 4 ways you could follow to fix the Lenovo keyboard not working issue.


1. Install the Latest Windows Update to Fix Lenovo Laptop Keyboard Not Working in Windows 10

To fix the Lenovo laptop keyboard not working in Windows 10 problem, you could try to install the latest Windows update. Take the following steps:

Step 1. Click the Start button and click the Settings icon.

Step 2. Click Update & Security.

Step 3. Click Check for updates and then wait while Windows looks for the latest updates for your Lenovo laptop.

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There are three more options, none are terribly hard to do, give them a go. I don't suggest installing their driver software per Step 4. Good luck.

Didn't make a difference. I am considering installing the driver software, although I'm reluctant to install anything Lenovo specific. I don't like that it came preloaded with Lenovo software in the first place, as I prefer to have a pure Windows install without manufacturer-specific crapware.

Thanks.