Xp recovery cd?

I have an amilo l6825. i purchased it from pc world in the uk in 2004. it came with windows xp home edition and it's the verification sticker on the back. last year the hard disk failed and i had to get a new one installed. when i got it back they had reinstalled windows but it was the professional edition. i didnt reckon much about it at the time but now i have encountered a few problems in that sp2 will not install etc. etc. and i'm worried that there might be problems if i try and upgrade to vista for example. i have found the recoextremely cd. when it starts it tells me that it can't upgrade from xp professional to xp home and so i will need to do a full installation and that i may loose files - what files will i loose? will i loose all my programs and files - will i need to format the hard disk??

Answer

Ok here's a fact, you have a coa you can validate any original copy using that number several times for the very reason you have just mentioned. microsoft would be besieged if every time a guy installed a bigger hard drive he had to buy another windows. you can chose not to delete the files on setup ps its an automated service has soon has windows starts it will validate. at your request