Most likely. My upgrade copy of Win7 came with two discs. One for 32-bit, one for 64-bit, but only one license key. So while I'd never do it, in theory I could install the 32-bit version.
And so long as you have some previous product that qualifies for the upgrade price, you'll be fine with that. Just as with all previous versions of Windows, the only functional difference between the upgrade and full versions is that the upgrade will ask you to provide some kind of proof of eligibility. Usually this means just putting in the XP or Vista install disc for a few seconds.
From time to time in the past I have found it useful to do a full reformat and reinstall of Windows (XP) to solve some intractable problem. I also want to be able to upgrade my motherboard etc., without having to buy Windows again. As a result, I am thinking that I need to buy the full retail version of W7 Home Premium. Is that correct?
Assuming that I do that, I would like to try the 64 bit version. I know that my PC is up to it, but I am not so sure about all of the programs that I use (some older games etc.)
Am I right in thinking that with the full retail version I could install the 64 bit version and if I later change my mind, replace it with a clean install of the 32 bit?

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