It has been answered here;
I am currently running a computer with XP Home SP3 on it, however I am planning to format the hard drive and 'start again' as it is extremely slow currently and want to start from fresh.
I have the licence key for XP Home SP3, but only a CD for XP Home SP1. Will I be able to reinstall from scratch using the SP1 CD with the SP3 licence key or will i need an SP3 CD? If so, how can I obtain one?