Need help with GNOME issues [FC17]

For a while now, GNOME fails to load on Bootup and reverts to fallback mode.

However, if I log out then I'm presented with the GNOME 3 login screen and GNOME 3 will then load and run (slowly, but it runs).

I also experience lots of Xserver crashes under fallback mode.

I think my best solution is to completely replace GNOME, even the login manager, but Fedora seems to use GNOME to kick off all other graphical desktops. Can I completely replace GNOME in Fedora 17?