What is the best way to backup my installed FIFA 06?

I would like to experiment with different patches and customizations. Yet I don't want to have to reinstall everytime something goes wrong.
I've tried copying the entire FIFA 06 folder in Program Files, which seems to work okay. But this file is huge!!

Would it be possible to pick out the really important files (provided I understood which files ) to backup and save myself a lot of time?

Let me know what you folks out there are doing.

Thanks.

I burn everything on DVD-RW + a complete backup on another hard disk, every single day. Doing that since I lost my complete modded for over a year Fifa2005 after an error... that won't happen again, ever.