I'm not sure if I understand your situation.
I understand that you wish to restore your computer to Windows XP Home which you previously had installed on the computer which you had also activated.
If this is the case, then you can do a full install of Windows XP Home on the computer and activate it.
You can install Windows XP onto the SAME computer many times while still retaining the ability to activate it. However you will not be able to activate it on another computer.
So to summarize, you can and (in my opinion should) do a FULL install. In-fact I am unsure that you would be able to do a repair install.
Best of Luck.
Ok, I recently had windows xp home installed on my laptop. I went to install xp pro. I got this copy of pro from my friend. THe coyp did not work on her computer, so it had not yet been registered. Well I found out that she received pro from someone else who did use the activation code. Now, I'm outa luck, gotta restart. I have the recovery disk with xp home; do I do a full install or repair install? If I full install it will ask me to validate windows, but it will not work because i've already used the code to activate the old xp home. I don't think a repair install will work though because it is going from xp pro to home. Help!