Windows XP Key

[landoni88]

Hi all, I'm new to these forums so not so sure on what sort of assistance I am going to get here. I've read all forums and have not found anyone to seem to have the same issue as me.

I had a laptop that I bought off a friend. It had windows 98 on it.
I uploaded windows vista to it and then stupidly lost the disc.
Everything was fine for a few months and I realised I had just about had enough with windows vista so I borrowed a Windows Xp home edition from a friend. I uploaded it all the way till the point of inputting the product key.
At this point he told me he hasn't got the product key :|.
So I had Installed windows xp home without a product key, and Cannot workout how to Basically, get rid of it.
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.
That is where I am up to so far.
Really looking for some helpful assistance.
Thank you all very much in advance.

[glc]

Using your legal XP Pro disk, delete all partitions and do a fully clean install using your legal key.