lost product key

I have mirosft xp professional with frontpage that I need installed on my computer. The problem is I don’t have it installed, I don’t have the product key and am ex friend took my ornial cd and has all the info. My compter came from the make a wish fndation. Is there anyway to find the product key of this cd. I don’r have any proof that the cd is mine becaue my ex friend took all that info is there anything I can do.