Are there any known issues with AMD Athlon X2 processors (namely a 4400) or ATI Hardware (namely an ATI 1900XTX)? I have been trying to install 3.6.9 on a friend's computer but it hangs when you run the program. No log files whatsoever.
Otherwise, the only thing I can think of is whether or not 3.6.9 still maintains MVE support. When I gave him a DVD containing all the FS2_open upgrades and related campaigns and stuff like that, it contained the MVE files and not the newer OGG cutscenes (I burned the DVD about 6 months ago, it had 3.6.9 RC9, I copied the entire DVD to his FS2 folder then downloaded 3.6.9).