Gnome missing as an option for log in desktop

[Arch Willingham]

I use FC6 on my laptop. While I have logged in to KDE to see what it looks like, I use gnome as my desktop. Tonight, I started my laptop and logged in once I got a log in prompt. I was watching TV and did not pay attention until it quit logging in and I noticed that it was the KDE desktop. I logged off and picked the option to use a different desktop but Gnome is no longer an option. Anyone have any idea why it would do that and how to get gnome back?

Thanks!

Arch