I am thinking of purchasing a used PC but i wanted to check a few things before I comitted to buying. My main issue is that it is not being sold with an OS. It has got XP Pro loaded onto it but the advert says that they are not selling the product key/licence with it so it simply for testing then should be taken off on receipt of the PC. What I want to know is can i keep that OS on with the product key and license or is that illegal? If i do have to change it, i can't afford to buy the full XP cd - how does the 'upgrade' XP CD differ? ( I have access to the upgrade version) I think i heard somewhere that to use the upgrade CD you need to have the previous product key (which i dont have)... I do have a Windows 98 full edition CD with product key etc - is there any way I can put that on the PC and then put the XP upgrade CD on after (eg. as i have then have the product code) Sorry this is long winded - hope it makes sense!