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DOS drivers for your CD drives? Error Code 7? I think you're making this a bit more complicated than it needs to be. WinXP doesn't use DOS at all, so for starters, you should completely wipe the hard drive and start over. Download Seagate's DiscWizard Starter Edition (for making a bootable floppy) and delete all partition info on the hard drive. You can also use DiscWizard to partition your hard drive if you so desire, or Windows can do it for you. Whatever you want.
Once the hard drive is "fresh" again, take out the floppy and put in the WinXP CD. If the problem was with the previous data on the hard drive, everything should go smoothly now. If not, report back with the new symptoms.
Computers are fun!!