I worked Flight Sim on earlier windows with no problems. I am on Windows 7 now and have problems. I have brand new ACER computer, on landing or taking off, the centre line lurches from left to right and is very unsteady. On some occasions I have a pilot, clad in flying gear, sitting in the middle of no where, with a propellor spinning merrily away, six feet in front of the pilot. What is wrong! Ken Garner.