Anybody else have recent problems with USB not working properly in Win 8.1? Within the last week or so, my system decided to stop recognizing any USB storage devices. Mouse and keyboard work fine, as does everything else USB, but suddenly no storage devices -- thumbdrives, externals, etc. -- will function. Device Manager shows the yellow exclamation mark on "USB Storage" under "Other Devices", and if I plug in a thumbdrive, it shows up under Devices and Printers with the yellow exclamation mark, but will not appear as an available drive.

My first thought was that some piece of hardware had malfunctioned... my mobo is older, after all, plus I do have a multi-port hub installed, which supports USB/SD/MMC/etc, and that could have blown -- but when I boot into another OS (like XP or Linux), everything works fine. So the problem is within Win 8.

I tried doing a "Refresh", but it stops with a message that "Some files are missing" and that my "recovery disk should provide these files", but I'm not sure how to go about finding them on there, or which files it means, or what to do with them once I find them. Suggestions, anybody?