Generally the 1st installation is the the 1st to appear
the 2nd installation is the 2nd to appear etc etc...
So it looks like you want to get rid of an xp installation ?
your 1 st install wll appear up the top.
your 2nd xp install will appear below it at the bottom of it.
So I'm guessing the way you explained things is that you want the 1st xp installation deleted/ removed ?
Now be very careful of using 2nd part programmes here my friend, because it sounds to me like you have simply re-installed windows over the 1st installation ? & if I am right then don't use any 2nd part programmes to delete any partitions for god sake or it''l delete both your windows xp installs god forbid.
Use the win xp cd, go through the motions of starting an installation... but this time delete the 1st/ top installation, once done cancel the installation so you sould be left with only the 2nd installation that you done, I think this is the 1 that your wanting to have ?
anys, hope I've helped... but please dont start deleting partitions with other software as it doesnt understand that you maybe have 2 xp installs sharing the 1 partition you know what I mean ?