I have the PMDG 747 Queen of the skies add on for FSX... lol I paid $25 for it at Target.   My problem... I have had it for about 3 months, and I can now start it up, from a cold, dark cockpit without using shortcuts, but I can not get it off the ground. I go through every procedure by the book, I do not have it overloaded(I have checked that repeatedly), but I can not get it to go faster than 140 on the runway at full throttle. I have tried everything including not having anything on the airplane(except just enough fuel to allow me to get to the nearest airport(about 30 miles away).    Do I just need to uninstall it and then do a reinstall?  I want to be able to fly my beautiful darling except she is being somewhat unreasonable!