computer logins in to blank blue screen

On startup, I get login window, enter credentials then I get a blank blue screen with only the mouse cursor and I can move the mouse on screen. I get no response from a CTL-ALT-DEL. No reponse from any keyboard activity.
I can boot into Safe Mode with Networking and can get on the Internet, I can map a network drive of other servers on my network. I can run some apps in this limited Safe Mode.
I cannot boot to full mode.
OS is Windows XP Pro with SP2