Hiya. I'm browsing around for a copy of Windows Vista + Windows 7 upgrade and came across this. http://www.newegg.ca/Product/Product.aspx?Item=N82E16832116677CVF Exactly what does it mean by "System Builders"? I'm under the impression that I'm limited to installing on a single PC. What happens if I decide to reformat the poor thing or starting changing parts on the computer? Also, do you know if the Windows 7 upgrade will have the same limitations? Thanks a bunch for your help, everyone.