system Freezes up when starting in system configuration utility

I recently changed the startup mode to System Configuration Utility and when
I start windows it gets all the way to the screen with the icons and than
comes up with a info box that explains that I made changes to the way it
starts up etc and the system is frozen.Nothing works, not even the pen or
anything. Any help on getting past this point on starting the system in safe
mode , anything ! Help....Thanks in advance