Macbook Fails Upon Software Update

i logged onto my macbook which indicated a software update. shortly after it was complete, a message stated i that i needed to restart the computer. i saw that is said complete so i pushed the power button. when the computer rebooted, a black box appeared that stated:
You need to restart your computer. Hold the power button for several seconds or press the Restart button.
Well, there is no restart butoon to push and when I push the power button, the only action that happens is this message box, over and over again.
I should note that in the top left hand side, there is code on the screen - does not look promising.
Can you help?

Restarts after Software Updates are best left to the machine to do automatically as it can take quite some time. For example the X.5.6 update on restart chimed, black screen, chime again, slow normal startup with the total time just on five minutes. Just leave things be and do not turn machine on or off.

Pop in your install DVD and boot holding down 'C' and see if the MB starts from that. If so run Repair Disk and check all is well. If you can get the machine up and running, download combo updates from the Apple web site.

Keep us posted?