Hi, I had my XBox modded at a vendor sometime last year.
They installed Evolution X, a file manager (I forgot what it was), and XboxMediaCenter for me.

I would like to update the XBMC so that it'll be able to play avi encoded with the newer version codecs and RealMedia files.
Is there any way to do it by burning the files I need on to a cd and copy them over the older version, or would I have to learn to FTP to the XBox to install from scratch?

Thank you very much.

I should image you can do either. Although I would say just to use the ftp method as its quicker. It's really simple to use and if you get stuck or cannot get it to connect then there are always some tut's around on here about it.