I have a pretty much default FSX, with only modified sound sets, default repaints and the overland airliners... no modifications to the original FSX... and the SP1 does wonders for my setup...so is there any advantage to reinstalling FSX for someone like me that never bothered with addons (oh yea, I do have the Alpha sim SR71 - but that doesn't use dlls...) ?? Peter

I do not think so... as a matter of fact, I hope not, because I would then have to re-install FSX as well : - )

The best way to play this is to put your FSX disk one in your DVD drive and run autoplay then choose the "Repair" option which wil reset any FSX files back to their original state.Then rip into SP1 and you should be able to go fly your add-ons without re-installation and no further FSX activation.This is the method I used very successfully. I also tried the complete reinstall method but I got no better performance and had a lot more work to do so I recalled the backup of my "Repair" install and have run with it ever since.John