Why the keyboard does not work

Without a mouse and keyboard, the computer can not be fully used. The touch screens of monitors, to the mass appearance of which all are prepared by their new operating systems by Microsoft, are still prohibitively expensive. Therefore, now the main interface of user interaction with the computer are these two devices. Software developers try to anticipate various situations, including the possibility of working in their products only with one mouse or one keyboard. These solutions do work, but there is no question of usability.

If the keyboard and mouse do not work, then this is akin to a catastrophe. The panic is reinforced by negative thoughts: "We saved on buying", "The repair will be a pretty penny", etc. First of all, you need to take yourself in hand and carefully assess the situation: it's enough that the computer turns on, that means financial costs, if they are needed , Will be insignificant. In fact, the reasons why the keyboard does not work are great.

Perhaps some newcomers will be surprised to learn that the computer keyboard is not just a plastic base with spring-loaded buttons (keyboard), but a full-fledged device with its own microcontroller. Having disassembled it, you can see inside the chip and several accompanying electronic elements - this is the controller or, if you like, a specialized microprocessor. It registers keystrokes of buttons and sends information about them through the port to the system bus of the computer, and then to the application.

So, here they are, possible reasons why the keyboard does not work: a malfunction of the keyboard microcontroller, an open wire or a plug, a port break in the computer, a program crash. Regardless of the reason, the user can only eliminate the problem with the wire. In all other cases more cardinal solutions will be required. The principle of the computer mouse is similar: it has its own microcontroller.

Keyboard breakages can be of two types: the keyboard does not work at boot and in the operating system applications. The operating system uses its drivers (specialized programs) to control the keyboard, so if one of them fails, it can not correctly process signals from the keyboard microcontroller. The simplest solution is to reinstall it. For Windows users, you need to follow the path "Computer - Properties - Device Manager - Keyboard" and remove the driver. After that, the system will require a reboot. Sometimes installation of the driver from the manufacturer, as, for example, Logitech can help.

Still more common faults, in which the user does not even guess why the keyboard does not work. The easiest way to determine its performance is to observe the status of the LEDs CapsLock, NumLock and ScrollLock. Immediately after turning on the computer, they light up for a moment and go out-it should be so, at this time the microcontroller passes the test and signals the health of its basic 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 in the right way. If nothing changes and it is still unclear why the keyboard does not work, then it should be connected to the computer via another port (connector).

It is useful to disconnect all devices connected to the same ports, because sometimes the keyboard does not have enough power. For USB keyboards in BIOS, the "EHCI Hand-off" parameter needs to be disabled, new operating systems do not need it, and it can interfere with normal operation. If nothing has helped, it remains to connect the tested keyboard. Earned - then the cause of the failure in the keyboard itself. No - there is a problem with the port connector or its controller.