Soft modding xbox?

I have an xbox (not a 360) and it has an X-bit chip in the back that has a green light that turns on but other then that the only thing it does is say "XECUTTer2" or something like that when I turn on the xbox. it doesn't do much else and I'd like to soft mod my xbox to be able to mod halo and other games. A walkthrough would be appreciated. thanks.