USB mouse and keyboard have stopped working. Everything was fine mid-afternoon yesterday, and a few hours later they didn't work.This is a Dell Lattitude 6400 running Windows 10 64 bit, with an external USB mouse and keyboard. I have ruled out the obvious - tested mouse and keyboard on another machine and they work fine. Rebooted, no change. Updated all drivers, no change. The mouse is recognized as a USB Optical Mouse when I plug it in, but when I go to Device Manager it is listed under "Other" (not under Mice and Pointing Devices) and when I check properties it says it has no driver. I try to update the driver, but no driver is found. Tried restoring to a previous restore point, no change. However, if I go into the BIOS setup, the optical mouse works fine. Also, when I booted from a Windows10 install disk, the optical mouse also worked fine. Since there doesn't seem to be an actual mouse driver (just built into Windows) I'm at a loss. I REALLY don't want to reinstall windows and lose all the apps already installed. Any ideas? Please? Thanks in advance!