After windows is turned on, the keyboard fails (non-hardware reasons). Solution

After windows is turned on, the keyboard fails (not due to hardware reasons). Today, when it is turned on, it suddenly finds that when the password is entered, the keyboard does not work. After trying the keyboard, there is no problem with the plug-in, it was strange to be able to enter the security mode. Yesterday was good, but it was useless today. After finding someone to change it for more than half a day, I didn't make it. Then I used the PE disk to delete the password and finally got into the system, on the device management page, the keyboard driver has a yellow exclamation point. It is preliminarily determined that the driver fails to be loaded and cannot be reinstalled. Later, I thought about the problem that may have occurred when I uninstalled the software yesterday. I found a solution and finally solved it. Here I will summarize it in case of similar problems in the future. Www.2cto.com 1. Open regedit in the registry, locate HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Class \ {4D36E96B-E325-11CE-BFC1-08002BE10318} 2. Delete UpperFilters, uninstall the device, and restart. Www.2cto.com 3. Then locate HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Class \ {parameters} 4. Add the string UpperFilters with the content of kbdclass, uninstall the device, and restart. Solve the problem! The driver of the PS/2 interface may have been tampered with due to the installation of some software, and the information in the Registry has been modified. Therefore, the keyboard itself is OK, but it cannot be connected to the computer, the driver in the middle has a problem. Put the problem and solution that this keyboard cannot be used normally here, so that you can query the problem with friends who encounter the same problem. This severely warns some undocumented programmers that the software must be clean and should not be uninstalled, resulting in a disaster, Nima, and almost redo the system.