Hi Светлана Баженов,

Please follow the below steps to resolve the keyboard issue.

1] The first thing you can do is, try to find if some keys or keyboard has broken physically somewhere. If there is a physical impact, there is nothing much you can do. You need to carry this laptop to the service center.

2] Take a brush and start cleaning the keyboard. Make sure you remove all the dust, and the keyboard is crisp and clean. You can use a laptop cleaning kit, or you may use an old toothbrush. Keep your brush dry and gently clean off your keyboard.

3] Another thing you can do to make sure the keyboard works when you have accessed the BIOS menu. Restart the computer and while it is booting up, hit the keys (usually Esc or Del) to open the BIOS menu. If you were able to open the BIOS menu and use the arrow keys to navigate, then we can assume the problem is with the software part and not the hardware part.

4] Now it is time to reinstall the keyboard drivers. You can temporarily enable the on-screen keyboard or connect an external keyboard if you are not comfortable without a keyboard.

Now to update the driver, open Device Manager from the WinX Menu. Now under ‘Keyboards’, you will find your laptop’s keyboard. Right click on it and select ‘Uninstall’. If you are not sure about your laptop’s keyboard, you can uninstall all the keyboards.
Restart your computer and check if you see its driver installing automatically. If not, again open Devices Manager, right-click on Keyboards and select Scan for hardware changes to install it.
After the driver is installed, check if the keyboard starts working.

5] If you believe that some external software or you might have changed the keyboard settings and made it unusable. You can reset keyboard settings back to default.

6] If the keyboard is working but not taking the inputs properly, you can perform a Clean Boot and check. Once there, you can check whether the keyboard is working fine or not. If it is fine, then probably there is some third-party software or service hindering with the keyboard in the normal state, which you will have to identify.

7] If you notice a short lag from the time you press a key and a character is displayed on the screen, then you need to disable Filter keys. What Filter keys do is basically ignores repeated keystrokes to make typing easier for people with hand tremors. But it can cause problems sometimes for normal or fast typing speed. To disable filter keys, go to Settings and then Ease of Access. Select keyboard from the left menu and find an option to disable filter keys. This might solve your problem.

These were a few tips that can get your keyboard working. Apart from these, you can use below ones:

Check for Crumbs
If you have a keyboard vacuum or a can of compressed air, give the nooks and crannies of your keyboard a quick cleaning. Hold your laptop upside down or at the very least at a 45- to 75-degree angle from horizontal and give the laptop a good shake.

Battery Check
Sometimes you have to take that "have you tried turning it off and on again" advice to the extreme. Shut down the laptop, remove the battery, wait a minute or so, replace the battery, and boot up the laptop.

Defective Keyboard
If you're still in your warranty period or have an extended warranty, then try your laptop manufacturer's tech support line. If they determine you're using a defective keyboard, you should be able to get it replaced at a service depot without too much hassle.

I hope this helps.

Regards,
Lokesh