Just my 2 cents. I had a similar problem where I couldn't control the mouse pointer to log on to desktop. I discovered that I had a game controller (flight sim rudder pedals) plugged into another USB port. At start up, WGT was recognising the rudder pedals as my main pointing device, not the mouse. Disconnected the rudder pedals and no further probs. So, have you another device plugged into a USB port that could be interfering?