Problem with Windows XP

Question

I had both Windows XP Home and Windows XP Professional loaded on my desktop. I was running XP Professional and I kept getting a message that my software wasn't legal. I loaded the XP upgrade CD and then I started running under XP Home. Now I can't see my emails that are on the XP Professional side, and some of my software isn't loaded on this side, and I get a message that I have a duplicate name on the network. How can I get everything on one side with all my emails and programs combined?