Need Help: Mice/Keyboard not working intermittently across district

So starting on Tuesday January 7th within our school district we are starting to see mice & keyboards (USB) intermittently stop working. Our users are logging off and logging back on and they will work for some time and then stop again. Some back ground information on our systems as well as things we have tried so far:
-All machines were imaged over summer with win7x64
-We keep up to date with windows updates through our wsus server (however we do not release hardware related updates, only critical & security windows updates)
-Everything was working up & until Tuesday, we have made NO group policy changes since then, last time windows updates went out to our network was Dec. 14th and they were working fine before the winter break
-It is happening on several different machines throughout our district, Dell optiplex 760, 9010, 790, as well as laptops with USB mice plugged in
Things we have tried:
-updating bios to most recent A18
-adding specific GUID for mouse, keyboard, & usb related devices for non administrative users to group policy
-un-checking setting for computer to turn off usb ports to converse power
-re-imaged machines & unchecked & hid the updates associated with MS13-081
UPDATE: After receiving some great advice from a lot of you guys I went ahead and started looking into the windows update artcle http://support.microsoft.com/kb/2862330, I tried removing KB2862330 on one machine as well as re-installing it on another, still with no success. I also discovered that on October 8th, when this security update went out so did 8 others. In short, 5 were for direct USB core stack & 4 were for Kernel USB. We took one of our labs that has about 20+ machines and on the first 9 we removed 1 update from each of that pack, then on another we removed all 9 updates, and then on another we re-installed all 9 updates.