Well, it's come to this. My attempt to understand and document the ways in which you can clean install Windows 7 with Upgrade media (see my previous article on this topic) has opened the proverbial can of worms. While I wish that Microsoft had stepped up to the plate months ago and simply described the ways in which this process can work, they have not, at least not adequately. And with millions of people purchasing Upgrade versions of Windows 7 without fully understanding what they've gotten into, it's pretty clear that someone needs to confront the challenge of figuring this all out.
Fortunately, I'm not doing this alone. Windows expert and writer Ed Bott is also working on the same problem, and we've been sharing information about the ways in which one might utilize the Windows 7 Upgrade media to install the new OS in various configurations. So I'll be cross-linking to Ed's own discoveries throughout this process. We hope to emerge on the other side with a much better understanding of what does and does not work.
[ Read Ed's open letter to Microsoft about Windows 7 upgrades.]
Fortunately, Microsoft is starting to help as well. The company sent along a small pile of Windows 7 Upgrade media and product keys for me to test with. I wish I had had this stuff months ago, but whatever: It's here now and I intend to use it.
So here's what I'm going to do: Over the next several days--weeks?--I will step through the various ways in which you can take an Upgrade version of Windows 7 and install it on your own PC. The various permutations of this process are astonishing once you really dig into it. Consider some of the following issues.
Going from 32-bit to 64-bit. While Microsoft does support an in-place upgrade from Windows Vista to Windows 7, it does not support an in-place upgrade from a 32-bit version of Windows Vista to a 64-bit version of Windows 7. (The reverse is also true: 64-bit to 32-bit Windows upgrades do not work.) Users that wish to move from 32-bit Windows Vista (or XP) versions to 64-bit versions of Windows 7 will need to perform a migration. This means you must backup any information from the existing Windows install, boot the PC with the Windows 7 install media, and then perform a Custom (not Upgrade) install. Yes, with the Upgrade media if that's what you have. If you choose to install the OS to the same partition where the previous Windows version lived, it will be overwritten, and your previous Windows install will be copied to a Windows.old folder structure.
You own a high-end Windows Vista version but want to "upgrade" to a lower-end Windows 7 version. It's not hard to imagine, say, a user with Windows Vista Ultimate who now wants to "upgrade" to Windows 7 Home Premium, or some other Windows 7 version that is lower in the food chain, so to speak, than the version they're currently running. How does that work? As it turns out, all Windows Vista users qualify for an Upgrade version of Windows 7. And if you are upgrading to an equivalent version of Windows 7 (e.g. Vista Business to Windows 7 Professional) or a higher-end Windows 7 version (e.g. Vista Business to Windows 7 Ultimate), then you'll have no issues: An in-place upgrade will work just fine. But if you aren't, you'll need to do a migration. However, in this case, you can choose to run Setup from your existing Windows install (choosing, again, the Custom install type). Or you can boot from the DVD. (Though, again, if you're going from 32-bit to 64-bit, you have to boot from the DVD.)
Students who qualify for the $29 dollar Windows 7 upgrade. College students with .edu email addresses can buy a downloadable version of Windows 7 Home Premium or Professional for just $29. But they don't get a standard ISO for some reason. Instead, Microsoft is distributing this package as a three-file "box" set that is designed to upgrade an existing Windows Vista install in-place. But what if the student is using XP? What if they want to go from 32-bit to 64-bit? There are many, many questions here.
These issues are just the tip of the iceberg, and every time I think I've figured something out, more questions are raised.
So let's just figure it out.