Possible Duplicates:
Where do I download Windows 7 (legally from Microsoft)?
Can I transfer a Windows 7 license to another computer?
Windows Activation FAQ: How do language, version, 64-bit or 32-bit, and source affect ability to install and transfer Windows licenses?

I've got Windows 7 32bit installed. I've just upgraded to 6Gb of RAM and need the 64 bit version to be able to use it. Do I have to buy another Windows 7 licence for this or can I reuse my existing one. If I can reuse it where can I get the installation media?

  • You don't need to go to 64-bit to use the extra RAM. I will post an answer detailing this solution shortly. – Breakthrough Jan 7 '11 at 17:34

You can reuse your installation key.

But you need to get your installation media from somewhere. Be careful where you get it...I personally would try to call Microsoft and explain the situation - they may be able to give you a place to get a copy of 64-bit Windows 7. Worth a try!

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    I do believe microsoft has downloads of the installation media. – Aeo Jan 7 '11 at 17:14
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    Great! Can you point me to a MS download of the media? – macleojw Jan 7 '11 at 17:15
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    @Macl superuser.com/q/78761/4377 – Sathyajith Bhat Jan 7 '11 at 17:26
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    got mine from here and it worked mydigitallife.info/2010/04/28/… – blsub6 Jan 7 '11 at 17:26
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    @blsub6 and others, that must be where I got my links to official downloads last time then. I can't seem to find them on the microsoft site anywhere. – Aeo Jan 7 '11 at 17:39

I know this does not directly answer your question, but this addresses the reasons for the question in the first place. The Windows 7 kernel DOES support a page-address extension capable of addressing up to 64 GB of RAM on 32-bit systems. This was artificially limited to under 4 GB due to licensing issues. Note that this has been supported since version 6.0 of the Windows kernel (which was Vista, 6.1 is Windows 7).

A group of programmers have released a kernel patch for Windows 7 to allow the usage of more than 4 GB of RAM under Windows 7. Click here to download the patch, or view more information about it. The patch basically modifies the Windows 7 kernel to be more like the Windows Server 2003 Datacenter Edition, which is compatible with up to 64 GB of RAM with the 32-bit kernel.

Note that individual processes will still be limited to 4 GB even if the system can access more. This is because of the way 32-bit programs work. It should be noted, however, that few programs actually reach the 4 GB limit (save for some graphic/video/modelling intensive software).

If you have been fine with 32-bit programs thus far, and don't require individual processes to use more than 4 GB of RAM, then this solution may be your best bet (especially because you don't comprise compatibility).

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    A kernel hack, sounds risky, is it? Anyone using it for a long period of time without issues? Thanks for the link. +1 – Moab Jan 7 '11 at 18:00
  • No problem. I have been using it for over a year with no problems on multiple machines. The good thing about the patch is you can still boot the computer up WITHOUT the patch if you absolutely have to. The patch simply adds another boot entry to the machine. Thus, you can still boot the computer without the patch (even if you previously used it), but obviously you can't use all your RAM. All I do once the computer is patched is select the patched entry as the default, and disable the OS list from being displayed on boot (if you wanted to revert, just hit F8 when your computer boots). – Breakthrough Jan 7 '11 at 18:05
  • Results from Virus Total on the kernel patch...virustotal.com/file-scan/… – Moab Jan 7 '11 at 18:10
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    Note that this program does modify and patch system files, which is the primary reason that it is flagged by some antivirus software. This was not detected on my computer (using Symantec AntiVirus 10, today's definitions), and I have used this patch without any ill effects for over a year. YMMV! – Breakthrough Jan 7 '11 at 18:15
  • I tried the kernel hack, but got the blue screen of death when booting up so I went for the reinstall option above. A reinstall doesn't do any harm anyway! – macleojw Jan 12 '11 at 12:08

To download directly from Microsoft I think you'll need a subscription. I don't know exactly how they work or the pricing.

The good thing is that the SHA1 hash is public Subscriber Downloads.

You can get your ISO file from some "untrusted" place and then check that the SHA1 signature of the file is the same. To check the hash you'll need sha1sum or a similar program, it's almost standard in Linux and there is a Windows version.

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