I will be building a new computer in October or November. I have a version of Windows XP Pro that I can install on the new computer. My question is is it worth it to install XP and buy the Windows 7 upgrade to save $80? or should I just buy the full version? If I ever have to reinstall my OS would I be able to? I heard once you upgrade from XP your XP product code is disabled. Also, what are some pros and cons? Like would there be features I couldn't access because of the upgrade from XP?