When on earth would he put ME on too?
Hannah: it sounds like you have one physical hard drive, split into 3 partitions (so that one drive acts like 3). If so, you should make sure you have no important data in the ME partition, and then remove that partition (and join it back up with XP).
I also note the other partition is called Backup. Do you use this for backing files up? If this is a different hard drive then that's fine, but if it's just another partition on the same drive as XP and ME, then it's not a real backup. A faulty drive would mean you'd lose everything, including your backup files.
To remove partitions etc., you can use a program such as Partition Magic (which will do it dynamically, without you losing data, hopefully). You may want to get someone who knows more about this stuff to help you out though.
If you do decide to go removing partitions etc., make sure you backup all your important data, onto either another hard drive, or CD or DVD.