Likely something has gone screwy in one your ~/[username]/ Gnome configuration files.
I had problems with my Gnome on my CentOS box today. (It didn't go white, but the panels were blank and it was unresponsive).
I killed X with CTRL-ALT-BKSP, then deleted all the dot-gnome-something files in my home folder as well as a dot-gconf-something file, restarted Gnome. Gnome recreated the files I deleted with default settings and was fully functional.
(This type of situation illustrates why I like to boot to the command line and start X from the terminal).
If you don't boot to the command line, you could try using sudo to remove them from your new working login, but that might not work since your new user is likely not in the sudoers directory. If it does fail, you could try this (I don't really have a good way to test it right now)
1. Login as your new user.
2. Open a terminal.
3. Type su [oldusername]. Enter your password when prompted. (By doing this, you su (switch user) to your old user name.)
4. Try sudo dir .gno* under your old user name, then rm all the .gnome files that turn up.
Another way would be to boot to a live CD, mount your hard drive, enter your home directory, and delete those files from the live CD, then reboot and test.
(I think I had the gconf-something--I think it was gconf-settings--because I had the gconf-editor installed.)
Edit: I see your user agent icon says Fedora. If you have a root login, just delete the offending files as root.
Last edited by frankbell; 04-15-2011 at 10:22 PM.