I've been thinking about posting this for a couple of days or so, since yet another "I have 32-bit Vista OEM and want to use 64-bit instead" topic appeared. That question gets posted quite a bit, and every time it does it is met with a helluva lot of misunderstanding and misinformation. So here's the 'truth' of it all. The following is fact, not opinion
If you have 32-bit OEM Vista, and want to use 64-bit Vista instead, you are most likely screwed for legality and legitimacy. If you want your 64-bit install to be 'legal' you're most likely gonna have to buy another license.
The ONLY circumstance in which you can legitimately change from 32-bit Vista OEM to 64-bit Vista OEM (or vice versa) is if you got your OEM license in the form of pre-installed Vista on a prebuilt system, and the manufactuer of that system has a licensing arrangement which allows them to provide you with the alternate install media! That's it. Any other means of changing from one to the other will not have full legality/legitimacy. If you purchased an 'OEM System Builder Pack' to get your Vista license (which is what most people posting here will have done) then you are screwed because you are not legitimately entitled to use the alternate.
Why? Read on....
Licensor or End User?
Most people who try to tell you that "Yes. It is legal." will quote you stuff from the Vista EULA. (End User License Agreement). Wrong document, I'm afraid.
When you purchase a Vista OEM System Builder Pack to use on your system you acquire a split personality. You become both licensor (as soon as you open the pack) and end user after you install and start using the thing. There are differing legal rights and responsibilities attached to those roles, and you are obliged to meet the conditions of both roles. That's because, as a person purchasing and using Vista OEM for your rig you are deemed to be the 'System Builder' whose responsibility it is to (first) assign that license to a device and (second) provide product support for the end-user's usage of it. In addition to the EULA, you have to adhere to the conditions of the Microsoft OEM System Builder's license.
So why does that stop me?
As the System builder/licensor you are the person who 'distributes' the license to an end user and also the person who has to provide product support for it. And you can only legitimately distribute what you got in the pack! If your System Builder pack was 32-bit Vista then that's what you are allowed to distribute, in your role as System Builder/licensor. And as the person responsible for product support, to remain a 'legal' installation for the end user that alternate install media has to come from you, rather than from Microsoft. Kinda hard to legitimately distribute something you didn't get and aren't entitled to get, isn't it?
But I got my 64-bit disk from Microsoft so it must be legal!
I'm sorry, but "I got it" and "I was entitled to get it" aren't always the same thing.
Microsoft provides an 'OrderMedia' facility on its website for the benefit of Retail Vista customers (who purchase the right to use either install) and Software Assurance customers (who also purchase that right). OEM System Builder customers get rights to use one or the other install, in accordance with which was in the pack they purchased. The install keys attached to that licensing arrangment are not supposed to even work with the ordermedia website. If, by some fluke of luck, your OEM install key gets accepted by the ordermedia website then that's an error, not an indication of legitimacy.
So does that mean I can't use 64-bit Vista if I've purchased 32-bit OEM?
Nope. It does not mean that at all. It simply means that you cannot legitimately/legally use it.
In actual fact, if you use your OEM install key with either a 32-bit or a 64-bit Vista install disk, it'll still 'work'. It'll put a fully functional Vista installation in place. The checks and balances in place cannot adequately ensure that every aspect and nuance of legality is met in every installation. It is up to your own honesty and honour to ensure that you are meeting all the requirements of 'legality'.
You can easy enough get it 'working', if you get your hands on the alternate install disk. But if you've swapped over, you just plain ain't 'legal'. Those who'd try to convince you otherwise are wrong!
.
If you have 32-bit OEM Vista, and want to use 64-bit Vista instead, you are most likely screwed for legality and legitimacy. If you want your 64-bit install to be 'legal' you're most likely gonna have to buy another license.
The ONLY circumstance in which you can legitimately change from 32-bit Vista OEM to 64-bit Vista OEM (or vice versa) is if you got your OEM license in the form of pre-installed Vista on a prebuilt system, and the manufactuer of that system has a licensing arrangement which allows them to provide you with the alternate install media! That's it. Any other means of changing from one to the other will not have full legality/legitimacy. If you purchased an 'OEM System Builder Pack' to get your Vista license (which is what most people posting here will have done) then you are screwed because you are not legitimately entitled to use the alternate.
Why? Read on....
Licensor or End User?
Most people who try to tell you that "Yes. It is legal." will quote you stuff from the Vista EULA. (End User License Agreement). Wrong document, I'm afraid.
When you purchase a Vista OEM System Builder Pack to use on your system you acquire a split personality. You become both licensor (as soon as you open the pack) and end user after you install and start using the thing. There are differing legal rights and responsibilities attached to those roles, and you are obliged to meet the conditions of both roles. That's because, as a person purchasing and using Vista OEM for your rig you are deemed to be the 'System Builder' whose responsibility it is to (first) assign that license to a device and (second) provide product support for the end-user's usage of it. In addition to the EULA, you have to adhere to the conditions of the Microsoft OEM System Builder's license.
So why does that stop me?
As the System builder/licensor you are the person who 'distributes' the license to an end user and also the person who has to provide product support for it. And you can only legitimately distribute what you got in the pack! If your System Builder pack was 32-bit Vista then that's what you are allowed to distribute, in your role as System Builder/licensor. And as the person responsible for product support, to remain a 'legal' installation for the end user that alternate install media has to come from you, rather than from Microsoft. Kinda hard to legitimately distribute something you didn't get and aren't entitled to get, isn't it?
But I got my 64-bit disk from Microsoft so it must be legal!
I'm sorry, but "I got it" and "I was entitled to get it" aren't always the same thing.
Microsoft provides an 'OrderMedia' facility on its website for the benefit of Retail Vista customers (who purchase the right to use either install) and Software Assurance customers (who also purchase that right). OEM System Builder customers get rights to use one or the other install, in accordance with which was in the pack they purchased. The install keys attached to that licensing arrangment are not supposed to even work with the ordermedia website. If, by some fluke of luck, your OEM install key gets accepted by the ordermedia website then that's an error, not an indication of legitimacy.
So does that mean I can't use 64-bit Vista if I've purchased 32-bit OEM?
Nope. It does not mean that at all. It simply means that you cannot legitimately/legally use it.
In actual fact, if you use your OEM install key with either a 32-bit or a 64-bit Vista install disk, it'll still 'work'. It'll put a fully functional Vista installation in place. The checks and balances in place cannot adequately ensure that every aspect and nuance of legality is met in every installation. It is up to your own honesty and honour to ensure that you are meeting all the requirements of 'legality'.
You can easy enough get it 'working', if you get your hands on the alternate install disk. But if you've swapped over, you just plain ain't 'legal'. Those who'd try to convince you otherwise are wrong!
.