Hi, I reinstalled Win 8.1 and have one last problem to resolve; There is no entry for 'Software Devices > Lightweight Sensors Root Enumerator' in Device Manager which (I believe) is responsible for Sensors > Capella Micro CM3281x Sensor and Invensense Sensor Collection devices to be listed with an exclamation mark. I've downloaded and installed both driver packs from the Acer website (Platform and Other) and manually installed (.inf) as much as possible but nothing seems to work. Any thoughts/help/suggestions would be greatly appreciated. FYI, running Sysprep in Audit Mode on Win 8.1 with Intel HD graphics driver (from Acer site) Cheers!