|As there is no DOS in Windows XP you dont have a DOS prompt but a Command Promt. If you got the Command Promt from the boot CD you are in the Recovery Console and there are limited things that you can do with it, especially if you don't have a fully functioning operating system. DOS is an operating system in its own right, which you dont have.|
If you are trying to repair the existing installation ignore the first repair option and wait till the CD has detected the existing installation then select repair. If you are trying to reinstall Windows XP just follow the prompts but keep out of the Recovery Console
You cannot do anything with Office 2000 from a command prompt without a working installation which you don't have.