"select operating system to start" frozen

Hello,

The computer in Microsoft XP, and when I turn on the computer it goes to the black screen with white lettering saying:
Please select the operating system to start:
Window XP Media Center Edition
Microsoft Windows Recovery Console

--The screen is frozen and none of the keys or mouse will work to select anything. Not sure what to do, so frustrating.
I have also tried turning the computer off and the same thing has happened each time.
Thanks for your help.