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I have a fairly new cpu/mb etc. and I'm running a 64-bit version of Windows 10. I did select the bios features for virtualization.
Unfortunately, I am unable to install, with Virtualbox, any 64-bit version of any distribution of Linux. I have in the past installed 64-bit versions of Linux, on this same computer. Or for that matter, I've also installed 64-bit versions of other versions of Windows as guests. When I say in the past, I mean, prior to upgrading to Windows 10 and maybe 1 year ago when I was running Windows 7 or Windows 8 as the host OS. I've had to reinstall my OS.
What do I mean by saying that when I try to install 64-bit guest OSes, it doesn't work? Well, basically, the 64-bit drop-down options either do not appear or they cannot be selected. If I try to just go ahead and use a 64-bit version of Linux that I downloaded, it will give me a message that 64-bit versions of the OS are not supported on this system.
The only uncertainty I have that just came to mind, is whether or not I downloaded the 64-bit version of Virtualbox. However, I did have the same problem in VMWare Player and it seems unlikely that I would have mistakenly downloaded a 32-bit version of both, when it was my intention to use a 64-bit version.
Again, my version of Windows 10 is a 64-bit version (this is the host OS). I definitely have 64-bit cpu hardware (Core i7-3770). Does anyone have any suggestions? Would this be something that must be set in the bios or within Windows after I boot into the system? Thanks, Bruce