Your Windows 7 computer may have recorded in the Microsoft Windows Kernel-EventTracing log, an event with EventID 3 and Level of "Error". The description reads, "Session "ReadyBoot" stopped due to the following error: 0xC0000188". You may also see this error listed in the Overview and Summary page upon opening Event Viewer.
The logging of this error will not affect the operation of your computer. ReadyBoot is used by the ReadyBoost service that optimizes the boot time of your computer to a minimum.