X session messed up after upgrading to fc6. How to reset Gnome.

["Monkey Pet" <monkeypet gmail com>]

Hi,  I just reinstalled fc6 (over fc5).  The installation went well.  However, when I copied my old home directory over, everything went haywire.  Now, when I login to the X session via gdm, I get just a cursor, nothing else, no icons, no menus, nothing.  

I want to keep my old home directory, but want to force it to regenerate whatever is needed for gnome... how do I do this?  What files do I delete or copy??  thanks.