Alternatively, you can use a 98 boot disk, boot up into DOS with it
Hard to imagine anything less helpful.
"Yeah, if you have a 10 year old CD lying around from when you upgraded Windows 95 back in 1999..."
You might as well have said "If you have 5 1/4 inch floppy drive..."
Chances are good that if you're asking this question at all, you don't actually have an XP install disk at all, but instead a "recovery disk" that shipped when you bought your computer from Dell or whatever. Possibly you only have a "Recovery partition" in which case you may be largely ****** depending upon how you installed vista over it.
If you do have a cd/dvd and it's giving you that error when you try to recover by COLD BOOTING WITH THE CD BY TURNING COMPUTER OFF WITH THE CD IN THE DRIVE AND THEN TURNING THE POWER BACK ON then your best bet is to format the hard drive with some other bootable media like a linux livecd and then boot the recovery disk again.
good luck.
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