I didn't get to try your latest advice, but hopefully your solution or mine helps someone else with the same problem. In any case, everything looks good in the Hardware Manager now. I'm wondering now if I may have turned off the computer while an update was still running. To my surprise, the keyboard and mouse were working! After I logged in, a dialog box popped up saying something to the effect of 'system updating.' The process looked like it was hung up at about 10% for 2 or 3 minutes, the quickly finished and another dialog box appeared, indicating that keyboard drivers were being installed. I fumbled around in the BIOS for a bit (the keyboard worked in BIOS, as expected), but I couldn't find any relevant settings, so I exited without saving and Windows loaded. I found a trick to get into the BIOS: Turn off computer by holding power button Very quickly unplug and replug the PC Hold Delete as PC automatically reboots.

Problem solved! But I honestly don't know how it got fixed.

After uninstalling the mouse, it will not work until after reboot so you'll have to navigate using the keyboard by pressing the windows key on the keyboard and then using the arrow keys to get to the restart menu. If this works you may to do the same procedure for the mouse. Check the box that says uninstall driver as well if one is present during the uninstall and then reboot afterwards. If there are no devices showing issues then double click on keyboards and then right click on your keyboard and select uninstall. If it won't update because of safe mode you may have to manually find and reinstall drivers for that device from the motherboard or computer OEM website. If there are any devices that are showing a problem, it will already be open to that device if there is one, right click the device and select update drivers and update automatically. Once in windows, if the mouse and keyboard are working, go into control panel and then open device manager. If you can get to the safe mode screen then boot via safemode. To fix this you need to add a Standard Keyboard Layout to the Windows on. Just because the mouse and keyboard don't work IN windows, doesn't mean they won't work prior to windows loading drivers. Windows 8 users may have problems using F12 to hide/display the Grid menu bars. So what you need to do is begin hitting F8 as soon as you power on the computer and keep doing so until the repair screen appears with safe mode and repair options.

Keyboard not working in windows 8