First of all this is a forum in Spanish language and we all were pleased if you use it. I understand you if you cannot because you don't know the Spanish language.
Your case is very strange, you said
So I had Installed windows xp home without a product key
you can't install a Windows XP without a product key; you said
I tried loading a Windows xp professional disc ( my own), ( and yes i had the product key for once:) )
But the Windows xp Home edition product key input would not dissapear.
it happens when de product key is not the correct one.
And the fact that you have a laptop with Windows Vista and before it had Windows 98, a strange case of course.
Any solution?
Yes, go straight on to an informatics shop and ask to them, we can't offer you a real solution because, here, it is forbidden to ask for serials and product keys. I am sorry.