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.
This error is logged before the first user ever logs onto the computer during OOBE when reaching the maximum file size for the ReadyBoot session log: "C:\Windows\Prefetch\ReadyBoot\ReadyBoot.etl" . The occurrence of this error will not affect operation of the computer. On a normal boot, the Superfetch process shuts this process down before the log file exceeds maximum.
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.