Check the EventLog for anything else happening at the associated time.
Also, do a backup and try
GhostBuster to remove all redundant drivers from the system, if that doesn't make a difference, then I'd probably remove the motherboard drivers and see if it works OK on the default Windows versions.
Failing that, you may have a hardware problem with the USB sockets no longer providing enough contact pressure to ensure reliable connection. No really easy fix for this but one thing I've done is slightly squeeze the plug in my fingers.
You can see in the image that this slightly bows the USB plug shield which increases the contact pressure a little. YMMV, but I've done it to good effect over the years, just don't go overboard on the pressure.

Another idea, I have a netbook with a USB port problem where anything plugged in will appear/disappear whenever the plug/cable is moved slightly, pulling out the USB plug slightly, (1 or 2 mm), fixes it.