VU stands for Vaio Update. It is an application that runs in the background looking for driver updates from Sony's support database. Since my model (VGN-TZ150N) is not supported by Sony for Windows 8, I have uninstalled the application altogether.
I recommend you check in Sony's support website if your system is supported and if so, if there is a newer version of Vaio Update, compatible with Windows 8.
I hope this is helpful.
HF21