If there is no readyboost tab in the usb stick properties, control panel -> administrative -> services -> readyboost -> double click it and make sure it says "Startup type: Automatic" -> make sure the service is running.
If there is no readyboost tab in the usb stick properties, control panel -> administrative -> services -> readyboost -> double click it and make sure it says "Startup type: Automatic" -> make sure the service is running.