I have a Microsoft brand USB device that acts as a receiver for a wireless Microsoft Keyboard and a wireless Mouse. When it's operating normally, there are LEDs on the device indicating Caps Lock, Num Lock and Function Lock, of which the latter 2 are usually lit. It is plugged into a Dell Isnpiron 531 with Windows 7 32-bit running on an AMD Athlon 64 X2 Dual Core processor 5000+. When the computer goes to sleep (the power indicator on the main box is flashing), I can wake it by moving the mouse. So far all is good.
However, something changed in, I think, the past couple weeks (I suspect due to a Microsoft driver update problem). Before the change, after waking the computer, everything would operate normally as far as I could tell, but now after waking the computer, the receiver has no lights on, and the keyboard and mouse are completely unresponsive (which is odd, considering the mouse woke up the computer).
There is a button on the receiver that's supposed to reset the wireless connection and flash the lights while it does so, but it has no effect in this state. It's like the receiver doesn't have power (but how would the system know I moved the mouse, unless the power was on until it woke up?).
I have checked the BIOS/CMOS settings or whatever you call them, and did not see anything related to USB in the power management section. I have checked Windows 7 device manager and ensured that all the USB Root Hub devices have the setting unchecked for allowing the USB power to be turned off.
Like I said, this was working before, and the only thing I can think of that's changed is applying Windows Updates.