I have a decent system, Intel Centrino Duo Core, 1GB RAM, 500MB graphics card, XP...but when I have ever installed and launched a non-default aircraft that is "FSX compatible", black spots appear, CTD and then I have to re-install FSX all over again.I'd love be flying all the great aircraft out-there like the EMB series and an A319.

You really need 2Gb's of RAM in your box for it to run hopefully halfway decent. RAM is really cheap right now also. I run on a 2 ghz single core.DaveoESSB

That's probably the main thing I miss about FS9, you could fly any add-on plane without any problems even on an average machine.