I bought my wife an upgrade to Windows 7 for Christmas. There was a deal on the upgrade package to Windows 7 Professional when I placed the order for the laptop she was getting me. Now, according to what I've seen on the intertubes, and even according to the instructions that came with the upgrade, if you're upgrading from Windows XP, you have to do what amounts to a new installation, wiping out your existing XP software and creating a new Windows 7 system. However, if you're upgrading from Vista, you can do a simple in-place upgrade. Just click "Ok" a few times, and soon you'll have a working Windows 7 system, with all programs and software installed.
Imagine our surprise, then, when the installation process moved forward a couple screens and then informed us that you cannot do an in-place upgrade from Vista Home Premium to Windows 7 Professional.
Why do they confuse the whole issue? As far as I can tell, there are no real differences between the OS versions, just later versions have some additional features. Theoretically, they could sell just one OS and the extra features as separate products. But then I guess they'd have to put their other features (like BitLocker, one of the features in Ultimate lacking in the "lesser" versions) out on the market to compete with other similar products (like the free and arugably superior TrueCrypt), instead of trying to hook people in by bundling it with the OS. (Isn't this the same behavior that landed them in court in the 1900s over Internet Explorer? Maybe it's not an issue now because it's only "bundled" if you pay extra for the extra software.)
Choking on this particular upgrade path doesn't even make sense to me. Isn't Professional supposed to be a superset of Home Premium? Why couldn't the upgrade disc add features that weren't there before?
But choke it did, and now my wife is in the process of collecting the installation files and a list of all software she will need to reinstall, because Windows does not work as advertised or documented; Windows 7 will not upgrade in-place over Vista, if it is "uncomfortable" with the mix of flavors.