I can almost bet this problem is on here somewhere. I just installed FSX Gold which contains the acceleration pack, thought I'd eliminate the problems with my standard FSX's SP1 and SP2. I downloaded PMDG777 for the second time and tried to install it on a clean 2nd HD after FX Gold. While trying to install PMDG 777 I get a message that my version is outdated and need to install FX's SP2. Then while trying to install SP2 I get the message I need to install SP1. On the SP1 download page it says do not install if the Acceleration Pack is alredy installed which it is I assume from FSX Gold. So I am stuck, I do not have my OS on my 2nd drive, so that should not have any thing to do with it. Last time I checked PMDG support was still down. My apologies if the answer is on here some where, still learning my way around.

Not sure if this should be on the PMDG 777 Forum.

Did you installed the 3 disks that came in the FSX Gold box. Two for  the FSX and the blue one is the Acceleration program? Just wondering.