Greetings --
Not to put too fine a point on it, you can't.
There is no way to reboot a WinXP PC into Real Mode DOS unless
you've set up a dual-boot system. The WinNT family of 32-bit
graphical operating systems, of which WinXP is the latest generation,
has never used, included, or "ridden upon" MS-DOS. The closest they
have is the Command Prompt window.
Bruce Chambers
--
Help us help you:
You can have peace. Or you can have freedom. Don't ever count on
having both at once. - RAH