This has to do with Windows activation - why is this running when my Windows copy is valid?? Was this added after recent KB update? I see "Software Protection" and "SPP Notification Service" running too?
Did you activate Windows? You may have a valid installation, but you still have to activate it somehow. slui.exe handles the legitimacy of the Windows license and provides a reminder to activate Windows. The file is not needed for the OS to work properly on an ongoing basis.