Windows 8 Pro upgrade: how to switch from 32-bit to 64-bit

You can't upgrade from 32-bit to 64-bit. Sorry the only way is a clean installation.

But Easy Transfer will help you:
http://windows.microsoft.com/en-us/windows-8/transfer-files-settings-another-pc

Also, to get to 64-bit from 32-bit, you must wipe your drive clean and start with a fresh install.

So you are caught between a rock and a hard place.

1. To stay with 32-bit is to limit yourself to 3Gb of memory and a slow machine.

2. To upgrade to 64-bit will give you the capacity for 8Gb of memory or more, but in this case will cost you a full 64-bit license.

You need to check which is cheapest:  64-bit Windows 8 Pro and free Windows 8.1 or a 64-bit Windows 8.1 Pro license.

I am using Windows 8.1 and there are some improvements and on the whole it was worth the upgrade (I had to reinstall Windows 8 to assure optimum performance).

.... Thinkpads_User

May I wind the clock back and ask this question: was there ever any way of upgrading 32-bit XP to 64-bit Windows 8 (given I had the DVDs for both, same license no.)?

And here's a chaser: could I (if I wished to) uninstall my 32-bit Win8 and upgrade my 64-bit Win7 to 64-bit Win8?

there was never a way from 32 to 64 bit
you can upgrade w7 to W8 if both are 32 or 64 bit

Your best option is: backup your data and install win 8.1 x64 clean. Will cost you nothing.
The license you own entitles you to install x64 OR x86, as you like. You are however limited to do an upgrade from a previous OS - but even this limit can be overcome: Download the 8.1 ISO, install it with a 8.1-key from here: http://technet.microsoft.com/en-us/library/jj612867.aspx and before activating, change it to your upgrade key. Works and is absolutely legal. Would however need a key for 8.1 pro, not "8.1".

Thanks - looks good.  Just to be clear: this one - Would however need a key for 8.1 pro, not "8.1" - refers to the (temp.) key I get from the site you mention?  (And yes, my upgrade DVDs are for 8 Pro.)

Your install needs to Windows 8 since that is what you have the DVD for. Once done, Windows 8.1 does not need a key.

... Thinkpads_User

If you start only with Windows 8.1, you have to purchase the key (since the system is not yet at Windows 8 64-bit if I understand the author above). Maybe the above will work but I saw some other articles elsewhere in my travels that it would not work. Try and see.

... Thinkpads_User

I tried and saw. That's why I recommend it. It saves time. Others did the same, just google the key from the MS page I linked, it became famous.

Thanks...I shall try myself but it has to wait for a couple of days now...(just received the nag about inactivity).

...another thought it may be unfair to raise in this thread, but if so can someone point me to the right one?

OK: I'm clearing the current Win8 partition before reinstalling using the recommended procedure.  When I get to reinstalling Win8.1 Does the installer notice that I have had a dual-boot setup with Win7 and deal with that, or do I need to re-create the dual-boot startup myself?

..and would it make a difference if I put the new Win8.1 on a different partition (in this case, on a different physical drive which I have acquired since setting up the existing dual-boot facility)?

Thanks.

If you are installing Windows 8.1 directly, it should work the same way as when you installed Windows 8.  

I cannot say for certain because I use VMware Workstation to do what you are trying to do and Windows 8.1 does not care about that.

... Thinkpads_User

I followed McKnife's advice - and fell at the last hurdle: my (upgrade) key was not accepted when I tried to Activate the new installation of Windows 8.1 (yes 64-bit).

Background: I downloaded the ISO following the advice here:

http://www.techrepublic.com/blog/windows-and-office/get-the-iso-you-need-to-create-your-own-windows-81-dvd/  The ISO is reported at 3,295,543,296 bytes.

I found I had to boot from the DVD in order to get a choice of target drive.

Following your advice I used the key for 8.1 Pro from the site you linked for the initial installation, and offered my own Product Key to activate Windows after installation.  It was rejected (repeatedly).

Any suggestions?

Thanks.

It will not be rejected via phone activation. Believe me, I did that process 5 times.

Right...so I phoned Microsoft just now (9am local time).  Was referred from dept. A to dept. B.  When I got up the Activation form and entered the Product Key (for the fifth time counting yesterday's failed attempts) it was accepted....  The technician did not claim full credit, but said that there can be problems with the interaction with their servers.

So thanks McKnife!

Stands out from the wide consensus that what I wanted to do is impossible.