Solution: Restart the computer. At the login prompt, select user <other>. Type in 'root' as username. Enter the password for any administrator account. If you only have one account use your password. Once the desktop appears goto the menu and start Terminal. In the terminal enter:
logout and try logging in as yourself.computername ~ # chown -R yourusername /home/yourusername
computername ~ # exit
NOTE: The chown command gives your user the proper permissions to access all of the files in your home directory, including all of the settings files that govern how your desktop looks. If a program installer writes to those files and fails to reset the permissions, then they can't be accessed the next time you log in.
(There is apparently no easy way to boot into console mode in newer linux distros. You may be able to use <ctrl><alt><F1> to switch out of the Gnome desktop and into a terminal session, or you may not. If you can, you can switch user to root and fix the problem there.)
hope this helps.