I suggest you take a look at this site Just a few seconds with open eyes would tell you what you need to know.  8)

There is a Compatibity Chart in the Downloads page & you can see that many FS2000 & FS2002 aircraft will work in CFS2 though you may not have ideal handling techniques.

Download one FS2002 747 (suggest Meljet or Project Opensky (posky) ) . Install it & it should work    but.... you will also need to install Panel & Sounds as these will probably be aliased to FS2002 default aircraft Panel & Sounds - but that's no problem either.

So ... Get your 747. Get a 747 Panel from the FS2002 (or FS2000)  Panels section & get some sounds from Sounds section & you're ready to roll

If you have troubles I suggest you take a look at Grumpy1's The Lair - linked from the main page here at simviation.

Happy Flying