To resolve the issue , please follow the sequence of TS steps listed below :
• Try to do BIOS defaults.
• Try to plug or re plug the external wired cable keyboard & mouse in different ports on the pc. (Or) Try connecting an alternate keyboard & mouse with the pc.
• If the pc is bootable in the normal mode then, look for the update KB4074588 (OS Build 16299.248) under the view installed updates section and then uninstall it. Restart the pc.
• If the pc is not bootable in the normal mode then try to go to the Advanced Options mode and try starting the pc in the safe mode and try to remove the above specified windows update KB.
• If the issue exists then try to perform system restore by selecting a date before the recent windows update.
• If the system restore is not fixing the issue then check with supervisor and then inform the customer about PC Refresh / Reset.
Reference Article : https://answers.microsoft.com/en-us/windows/forum/windows_10-hardware/keyboard-and-mouse-not-working-with-windows-10/94c0f66b-f0d9-4299-b05e-55dd25315cfb