Curious to know whether the original poster had any similar infections. I also installed some Windows updates but this was well after the keyboard stopped working. However I was able to clean my system using Malwarebytes' Anti-Malware and McAfee AV - the databases are up to date and the scans are running clean. What has changed? The timing of this coincides suspiciously with a malware infection yesterday (Windows XP Smart Security 2010, and some viruses that tagged along I think - including, but not limited to, ertfor and wmpscfgs.exe). I get the same erro 38 if I hot connect the keyboard in Safe or Normal mode, but if I reboot into Safe mode it goes away. The media/function keys seem to work in Normal mode. Num lock indicator is 'on' after bootup and can't be turned off with the keyboard. It is when I try to launch in Normal mode that the keyboard stops working - non functional when I get to the login screen, and thereafter. Keyboard works fine pre Windows boot or when running in Safe mode (by fine I mean the regular keys work - not the extra media / function keys, which I understand to be a normal thing for Safe mode). I also went as far as to remove all USB roots and controllers and rebooting to let Windows reinstall the whole lot. I've tried every uninstall/reinstall permutation I could think of (including in both Safe and Normal mode). I get the same problem regardless which port I use for the keyboard, and when all other USB devices are disconnected. All other USB devices work fine (hub, external HDD, wireless mouse, SD card reader). The onboard keyboard and touch pad work fine.

I don't believe it to be an issue with the keyboard itself as I have tried 2 other working keyboards with the same results.

If it’s still not working, try removing the USB hub and. If you use a USB hub between the device and the PC, make sure the hub has power. Try using a different USB port on your PC. USB keyboard was working fine for months but 'quit' suddenly yesterday - same symptoms as reported in the original post (error 38 on the HID Keyboard Device). Unplug USB cables and wait for a little while for the device driver to be unloaded by Windows, and then plug the device back in. Dell Latitude D610 laptop, running Windows XP SP3. I am having similar grief as the original poster.

Keyboard error windows 8