About half an hour ago Windows informed me it was trying to install software for an "Unknown Device". However, it failed. Using the Control Panel I checked the device's properties, and discovered that it was reported to be occupying a USB port which had nothing currently plugged into it. The device then disappeared from the Devices and Printers menu.
I'm running Windows 7, and I'm curious to know what the possible causes of this are. It seems slightly odd and suspicious that Windows would randomly report a new device for no reason.