I've finally given up the ghost on getting my FS2004 to work decently on my current specs and have uninstalled it. I have just tried to install my old FS2002 instead and it wont let me. I keep getting an error message at 30% while insalling the jetranger textures.
I've had this problem before and managed to find a way around it but microsoft have taken down the FS2002 support and i cant remember what to do.
If it helps you can click here to see the old post.