Ive got an issue

I recently reformatted my dell, and installed XP on a clean drive..No partitions.
When I reboot the computer I get an option to start one of two operating systems listed..
I only want one to run, and do not see any other OS listed when I poke around on the hard drive.
Any help would be greatly appreciated. I just wonder what I did.

I guess you did a quick format, and not a full one. You can get rid of the obsolete XP operating system listed in your options. Go to Start and Recovery in your Advanced System properties and edit system startup. Delete the obsolete option. Make sure you don't delete the one that belongs to your working XP as then you wouldn't be able to boot to your XP at all.