CentOS 6 does not show any desktop icons or anything in the panel

I was using CentOS 6 in VirtualBox fine for a couple of days. Now, when I login via the GUI user prompt, all I get is the background screen, no icons, no menubar, nothing. I am not terribly familiar with UNIX, but have used it in the past. That being said, if you need me to locate error messages to help diagnose this, please be specific as to where to locate files or specific commands that you would like me to execute, if possible. I have gotten to the GRUB prompt, but don’t know what to do from there.

I am reposting this question as the one for CentOS 5 had no visible answers.