Without a mouse and keyboard, full use of the computer is impossible. The touch screens of monitors, for the mass appearance of which Microsoft is preparing all of them with their new operating systems, are still overly expensive. Therefore, these two devices are now the main interface for user interaction with a computer. Software developers are trying to anticipate various situations, including in their products the ability to work with only one mouse or one keyboard. These solutions do work, but usability is out of the question.
If the keyboard and mouse do not work, then this is akin to disaster. Panic is supported by negative thoughts: “Saved on a purchase”, “Repair will cost a pretty penny”, etc. First of all, you need to pull yourself together and carefully evaluate the situation: it is enough that the computer turns on, which means financial costs, if they are needed will be negligible. In fact , there are a lot of reasons why the keyboard does not work .
Perhaps some beginners will be surprised to learn that the computer keyboard is not just a plastic base with spring-loaded buttons (keyboard), but a complete device with its own microcontroller. Having disassembled it, inside you can see the microcircuit and several related electronic elements - this is the controller or, if you like, a specialized microprocessor. It registers button clicks and sends information about them through the port to the computer system bus , and then to the application.
So, here they are, possible reasons why the keyboard does not work: a malfunction of the keyboard microcontroller, a broken wire or plug, a broken port in the computer, a program failure. Regardless of the reason, the user can fix only a problem with the wire. In all other cases, more radical decisions will be required. The principle of operation of a computer mouse is also similar: it has its own microcontroller.
Keyboard failures can be of two types: the keyboard does not work at boot time and in applications of the operating system. The operating system uses its drivers (specialized programs) to control the keyboard, so if one of them crashes, it will not be able to correctly process the signals from the keyboard microcontroller. The easiest solution is to reinstall it. For Windows users, you need to follow the path “Computer - Properties - Device Manager - Keyboards” and remove the driver. After that, the system will require a reboot. Sometimes installing a driver from a manufacturer, such as Logitech, may help.
Nevertheless, malfunctions are more common in which the user does not even know why the keyboard does not work. The easiest way to determine its performance is to monitor the status of the CapsLock, NumLock, and ScrollLock LEDs. Immediately after turning on the computer, they light up and go out for a moment - it should be so, at this time the microcontroller passes the test and signals the health of its main logic circuits.
Some older computers are initially configured to work with PS / 2 keyboards, and USB device support is disabled by default. In this case, you need to connect the PS / 2 keyboard to the computer and configure everything as needed. If nothing changes and it is still unclear why the keyboard does not work, then you should connect it to the computer through another port (connector).
It is useful to disconnect all devices connected to the same ports, because sometimes the keyboard does not have enough electrical power. For USB keyboards in BIOS, you need to disable the “EHCI Hand-off” parameter, new operating systems do not need it, and it can interfere with normal operation. If nothing helps, then it remains to connect the tested keyboard. Earned - that means the cause of the breakdown in the keyboard itself. No - there is a problem with the port connector or its controller.