Some USB devices randomly disconnect

Hello all,

I migrated to Windows 8 a little while back, and all have been going well until recently. I started having some issues with some of my USB devices randomly disconnecting from my computer. Usually it's the same few devices, including a network adapter, Bluetooth dongle and a wireless touchpad. Other devices, like my keyboard, continue working as normal.

I tried moving the problem devices around to different ports at one point, and I turned off USB selective suspend, both of which seemed to help for a while, but it started happening again. It's sporadic at best, and I can't pin down an exact cause.

Here's some potentially useful information: whenever the devices disconnect, if I go into Device Manager and disable the first "USB Root Hub" on the list, the devices begin functioning again. I'm not sure what this could be a sign of, but I hoped someone here might.

This past time, after disabling the Root Hub, I went to put the computer into Sleep, which just hung. I finally rebooted it, and I tried to enable the Root Hub again. The first time resulted in an IRQL_NOT_LESS_OR_EQUAL and the second resulted in a SYSTEM_THREAD_EXCEPTION_NOT_HANDLED. The third time worked, though, and the devices all began functioning again...
(I have both MiniDumps from those two BSODs if that'd help at all. Just let me know.)

Could this be a Windows problem, or is it a motherboard problem?