Windows XP home and pro on my computer.I only want one

My computer is realy messed up, I somehow ended up with xp home and xp professional on my computer. I want to get rid of the home edition, when I installed xp pro I thought it would overwrite, anyways I am not sure how to uninstall windows xp home edition without messing my computer up.I appreciate any help. Thanks.
P.s I just bought this computer and when I started it( with xp home) it says it needs to be activated..then proceeds to say it is already activated but nothing comes up..no desktop,no start menu etc..so I installed xp pro edition.

thank you

Hi JeanM

According to me, you need to reinstall the xp pro on your system as there is no other way to uninstall one os while keeping the other one. But keep this in mind that when you install the os this time you first format the drive inorder to completely remove both the previous installations.

I have no idea how to format and my computer came with d: drive as the primary drive, can you beleive I bought this at a computer store.lol...It came messed up so I installled xp pro from a cd...now I have windows and windows.0 on my d drive.

To format your hard drive, insert the Windows CD (Home or Pro which ever you want) on the CD ROM drive and shut down your computer. Now start it again and press F8 (or whatever button that allows you to go to BIOS) and select CD ROM as the first boot device. Now your computer will boot from CD ROM. Install the Windows once again. But remember whenever it asks you to format your hard drive or you want to repair it, select format the hard drive. Next it will ask you to take the backup of data available on the drive. Follow the procedure if you want to backup the data or else you can simply ignore the message and move further.

Hope I was clear and helpful to you.