I bought my current computer pre-built in 2009 before Windows 7 came out, but Windows sent me a disc to upgrade my operating system from Vista Home Premium to 7 Home Premium. Recently I've been looking at new motherboards and CPUs, and I know I'll have to reinstall Windows on the new hardware. So I was wondering, is it possible to reinstall Windows directly from the upgrade disc or do I need to install Windows Vista on it before I can use the upgrade?