Recently, Windows 7 RTM has been made available for MSDN and TechNet Subscribers including Windows 7 Beta Program participants(Invitation only). In past few days, I have received a question over size of Windows 7 ISO images and their SHA1 and CRC.

The SHA1s and CRC are all different for each Windows 7 x86 ISO and x64 ISO. Why?

MSDN and TechNet websites are offering separate x86 and x64 ISO images of Windows 7 for each edition, even the size of ISO images are same. That’s quite strange thing.

Microsoft has dropped pick a desired edition approach from a single ISO. The deal is that still each ISO is an ALL in ONE disc that have every edition. However, each ISO has been pre-configured to install the version that is mentioned. You won’t get a drop down or choice or option wizard, when you go through the installation as like Windows Vista, because Windows 7 accept product key at first logon. Where 99% things are done.

So suppose, you download the Windows 7 Home Premium ISO and when product key is prompted; you put Windows 7 Professional x86 product key. What will happen is that it will deny that key.