Reinstalling XP after changing to Win 98

Can anyone help me? My PC came bundled with XP Home Edition and a manufacturers XP recovery disk. However, we decided in the short term to revert to Win 98 for the sake of compatibility issues that we didn’t have the time to work through. Now, however, we’d like to go back to XP but are unsure of how to do it.

I understand that the hard drive has to be reformatted but the disk seems to be using installed setup files and seems reluctant to let me. I’m worried that if I format the hard drive the installation cannot go ahead.

Do I need to do a dual boot, and then format the Win 98 drive once XP is up and running? If so, how would I go about this?

Thanks for any help you can give me.