ok, well im building a new computer and this is the first computer i've built and i was going to get windows 7 for it but when i went to go buy it i realized there's windows 7 home premium upgrade and windows 7 home premium full. i went on google and searched it up and it said the upgrade only works if you have a previous version of windows on it and if your building a computer you need to get the full version. is this true?? because the full version is more expensive and, like most people, would rather just buy the upgrade.