Can I upgrade Windows 7 from Home Premium (64-bit) to Ultimate (64-bit) using reinstallation DVD?
Note: I'm not using an Anytime upgrade DVD.
The DVD install disc for Windows 7 (regardless of edition) cannot be used to upgrade an existing Windows 7 installation. Microsoft wants you to use the Anytime Upgrade feature to do in-place edition changes.
I'm assuming you came into owning a valid Ultimate copy (or at least a key for one). I've known students to get them through Academic Alliance and such and wanted to upgrade their current PCs which usually already had Home Premium on it.
Since it's a full retail product key, it doesn't work for Anytime Upgrade, and putting the disc in will probably only give you the option to clean install. This will backup the current Windows directory and install a whole new one. The problem, as you no-doubt realize, is that this means you lose all of your registry settings and user profiles. Your applications and games will still technically be on the computer, but Windows won't know about them since as far as it is concerned it's a fresh copy and you've not installed anything.
There is a trick, however, that can fool the install disc into thinking you already have a given edition and it'll let you do a repair install. This effectively upgrades you. Many users of the Windows 7 RC used this to "upgrade" to the retail version once released even though Microsoft officially said they'd need to start fresh with a clean install.
You can find a guide to the above trick here:
The above trick only works for upgrading a Release Candidate install. If you have a retail or OEM Windows 7 (such as Home Premium) installed it will not work.
Also, all Windows 7 DVDs contain the full Ultimate edition and can (and do) install any lower edition. There is a single file on the disc that tells the installer which edition it should install which is why you don't get asked during setup. If removed, the installer will let you pick. This is useful if you buy or receive an Ultimate edition product key but not an Ultimate DVD and you don't want to have to download an entire copy (this can take quite some time on slower connections). If you still have your Home Premium DVD, you can still use the Ultimate key with that and install the Ultimate version. You'll have to use both the trick mentioned above as well as this trick:
OEM disks cannot be used to "upgrade" any OS to any other OS. (this includes win7 home -> win7 ultimate) OEM by definition is only distributed by "Original Equipment Manufacturers" on "NEW" hardware... and as such, Microsoft went through a lot of trouble to prevent users from buying an OEM license & upgrading their current OS. This is both "illegal" and deliberately prevented by Microsoft. The only legal option and recommended method by Microsoft, is to buy either a "retail" license or an "upgrade" license... and install using the disk that comes from it.
If you have an Ultimate Key and you don't want to re-format - just run the Anytime Upgrade application on your system and enter your key.