I'm trying to reinstall my Windows XP Home edition operating system into a Dell Dimension 8400 machine. I have the operating system CD that came with the computer and when I boot into it, it takes me through the usual start-up sequence and eventually gets me to the Windows Setup Window where I have to choose whether to continue with a complete reinstall, repair or quit. I cannot choose any of these options. It would appear that my keyboard isn't operative or the system has frozen. Any ideas how to work around this problem?