You can download Windows 8, and a Windows 8.1 upgrade for free, direct from Microsoft, provided you have a valid product key.
Both are on Microsoft's Windows 8 upgrade, product key only site.
Complete Windows 8 ISO:
Clicking the Install Windows 8
button will download an executable installer which will download the appropriate Windows 8 ISO, based on the product key you provide.
Windows 8.1 upgrade:
Clicking the Install Windows 8.1
button will download an executable that will provide you with a Windows 8.1 upgrade installer download.
Complete Windows 8.1 ISO:
If you want to download a complete Windows 8.1 ISO, you can do so as well, but there's a little bit of a trick to it.
- At the Microsoft Windows 8 upgrade, product key only site, click the
Install Windows 8
button to download the executable installer.
- Run the executable installer, input your product key*, and download the appropriate Windows 8 ISO.
- Once the download starts, close the setup program.
- Return to Microsoft's Windows 8 upgrade, product key only site and this time, Click the
Install Windows 8.1
button instead, this time, and it will begin to download your complete Windows 8.1 ISO.
- Success!
And no, no one seems to know why the the process for downloading the complete Windows 8.1 ISO is more convoluted than getting the complete Windows 8 ISO.
*As noted in the answer here, The Windows 8 downloader for the ISO will not accept Windows 8.1 product keys, so you will have to use a generic placeholder key (334NH-RXG76-64THK-C7CKG-D3VPT
for Core, XHQ8N-C3MCJ-RQXB6-WCHYG-C9WKB
for Professional) if you only have a Windows 8.1 license. This placeholder key will not let you activate Windows, so this is key will simply allow you pass the key check on the Windows 8 downloader, and allow to proceed to downloading the Windows 8.1 ISO.
1
Same question for Windows 7: http://superuser.com/questions/78761/where-can-i-download-windows-7-legally-from-microsoft
– Wilf – 2015-02-17T22:25:46.957http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media – Wilf – 2015-02-21T22:02:01.507
1Doesn't dream spark offer a regular html download? they use too... – TheXed – 2012-10-27T02:20:08.347
No, they don't offer a regular html download. For downloading windows 7, the following post http://superuser.com/questions/78761/where-do-i-download-windows-7-legally-from-microsoft has the links to it. So I am looking something similar for windows 8.
– Ishan – 2012-10-27T03:36:02.620I completely feel your pain. Their "secure download manager" is so terrible. However, if you give Microsoft a bunch of money and get MSDN you get good ol' HTTP downloads – Earlz – 2012-11-08T21:54:26.497
1There are torrents of official ISOs available on the internet. Just google the filename. Remember to check the SHA1 afterwards to ensure that you have the genuine file! – kinokijuf – 2014-04-24T11:27:31.020
@kinokijuf likely those images are marked and won't work, even with a legal key. – Joshua Nurczyk – 2014-04-27T21:14:37.167
@JoshuaNurczyk what do you mean by “marked”? – kinokijuf – 2014-04-27T22:05:06.840
There are checksums and such on each Windows install disk, starting with I think Vista. This helps MS track which ISOs have been shared as well as limiting which keys will work with that specific ISO image. This means the HP OEM ISO can only be installed on certain HP hardware IDs. – Joshua Nurczyk – 2014-04-27T22:17:30.407