What do you mean by "formatted"? The term 'format' refers to file systems. Did you wipe the hard disk--ie, remove all formatting? Or did you add partitions and format a file system on those partitions?
If the latter, remove all partitions and start over. If the former, make sure your bios is set to boot from CD, press any key at the "boot from CD" prompt, and let XP create and format your partitions for you.
How to obtain Windows XP Setup boot disks,