OK, thanks. I assume that you have set this machine up with SPFDisk to allow booting into multiple operating systems. Do you get the message immediately, before the OS boot listing? If so, then you may need to reinstall SPFDisk. But if you get it while actually trying to boot Windows (or if Windows is the only OS) then that suggests that the Windows boot sector is corrupted. In that case, you c an try a Windows repair - here are the instructions:
Here is a pictorial to help you see what to expect
Did you get to this screen?
There is a list of steps with screen illustrations on this site - the list of step by step instructions is below the screen sample. I think I missed this step in my list of instructions - sorry.
Hello. You are in the wrong place. It is very confusing, but at that "Welcome to Setup" screen you must press "Enter" to "Set up Windows XP now", and then accept the license agreement and THEN press "R" to repair. Just make sure you don't press "Esc" to install a fresh copy of Windows. The CD must have been programmed by someone at Microsoft with a strange sense of humor.