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I'm considering migrating to Windows 7 Pro, downloaded from Academic Alliance. I have somewhat of a personal problem though, I usually format and reinstall an OS multiple times during the period I'm using it. So before going on and installing 7, I'd like to know what's the limit to the number of times I can perform an installation?

On a kinda-related matter, can I have it installed at multiple machines? It's not like I'm gonna set up a network with it, but in the case I'm pleased with 7, I'd like to have it running on both my desktop and laptop (of course, it's not like MS would know the difference between that and a network...)

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That's incorrect. The 32Bit and 64Bit key is the same for Windows 7 – BinaryMisfit Dec 3 '09 at 14:22
@Diago: You will be allowed to "purchase" 32b AND 64b Media seperately, each will garner their own unique key. From what you've said that means you can select both, use one 32b or 64b .iso, and you'd be able to install either twice legally. – Ande Dec 3 '09 at 14:36
up vote 7 down vote accepted

One machine at a time per License Key.

If you uninstall it (ie: Wipe a computer on which it is installed) you can reinstall it on another computer.

Installing it multiple times on a single machine may cause a problem as there are AA (Academic Alliance) and RTL (Retail) Keys. Academic ones are supposed to activate once, Retail activation can be used may times.
I have used keys from MSDNAA multiple times however, so I suspect RTL Keys are sometimes distributed, and either way they are both covered by the same License.

If activation fails for a subsequent install or you want to install it on a different computer after you have uninstalled it on your current one, make a quick call to MS and they should give you a code to complete activation.

MSDN Subscription Software Use Rights contains…

Need the full details? Software use rights for customers who have purchased the license through a Microsoft Volume Licensing program are governed by the Product Use Rights Document . All other MSDN Subscribers are governed by the Retail Software License Terms select “MSDN Subscriptions” for the Product Name).

Which leads you to… Microsoft Product Use Rights, Product List, and Licensing Topics …excerpt below:

Desktop Operating Systems – per copy, per device license You must acquire a license for each device on or from which you access or use the software (locally and remotely). You may install only one copy on the device. You may install that copy on the host operating system or in a virtual (or otherwise emulated) hardware system. In Volume Licensing, the desktop operating system license is an “upgrade license.” You may only acquire upgrade licenses for devices for which you have already licensed a “qualifying operating system.” A list of “qualifying operating systems” that qualify for an upgrade license is contained in the Product List, which can be found at Microsoft Product List for Volume Licensing. If you acquire “Software Assurance”, you have the right to use Windows Vista Enterprise Edition on the device instead of Windows Vista Business. This also permits you to run up to four additional copies or instances on the device.

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It's the first time I ever used Super User and I'm impressed. Many thanks! – S.O. Dec 3 '09 at 14:29

Its not about the times you can install, but the times you can activate. Go ahead and install as many times as you like, but I think you only get 15 or 30 days before you are forced to activate.

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Installation takes about 15 minutes, much less than xp installation on the same computer. Why do you have to reinstall? Maybe make an image backup immediately after a fresh installation is finished. I use a usb to boot up made from Active@Boot.

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As for windows XP, I installed and activated it many times (4-5). So, I thinks the same is correct for W7P, so go ahead.

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You didn't state which AA subscription you have. It would also be helpful if you calrified your use of the AA MSDN software. Is this on your school computer, home computer, is it for personal use, school use, etc. Also, have you read the AA Usage Guidelines and License Terms?

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I believe MS has a trial of Windows 7 Enterprise that could be used to see if you like it. That way you do not activate your legitimate licenses too many times and have to expalin to MS.

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I've reinstalled my PC's many times.. since I also do programming and test software for companies my windows gets screwed many times.. The MSDNAA key I could use up to now maybe 50 times. Doubt there's a limit. Each time you destroy your windows with some test software, test compilation, or whatever, you simply re-install and call MS activation by phone. Thus far I haven't hit any limits. But, not sure if you install it on dozens of different hardware setups.. I always use the same 3 different PC's I'm using, except for replacing Video-Cards, HDD to SSD, etc i usually don't change the Motherboards.. So I'm not sure if you want to install it on 10 different motherboards if that's not possible.. But reinstalling on the same hardware I can fairly say:"unlimited even for unusual users like me"

Add: I must add, I have 3 different MSDNAA keys for 3 PC's. I share the PC's with my roomies. So I'm not sure even if you can activate on 2 PC's at the same time! But as long as you stay with 1 key on the same Hardware, there seems to be no limit

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From the FAQ:

You can install it in several computers as long as you own such computers.

AFAIK: I think you can install the OS as many time as you want. But im reading the FAQ (in spanish) and it sort of says the key only can be used once.

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