I just purchased a Realflight G3.5 and it works great on my wifes laptop, (1-2 year old Compac I think) but when I run it on my Dell E510 the plane doesn't move smoothly, it speeds up and then slows down. When I installed the simulator on both units, it said I need Direct X 8.1 which it downloaded on each computer. ( I don't know if this is relevent or not, I'm kind of a computer retard, so reply accordingly!) I know it's hard to diagnose anything without seeing it, but are there any ideas out there? Ross