Hello, I am currently using Vista Ultimate 32bit, and I'm trying to upgrade, at least what I think is an upgrade to Vista Home Premium 64bit, when I put the installation disk in, it tells me I can not run this version, on this version of vista, and when I restart it its like my cd-rom/dvd drive just disappears and I have to pop the disk out to get it working again..how do I get rid of the vista ultimate so I can install the new vista?