If you're having difficulty installing 64-bit Windows 7 on VirtualBox, the likelihood is that your host computer isn't quite up to the task, or if it is, such functionality is disabled in the BIOS. This cannot always be undone, however.
Advantages of Virtualization with VirtualBox
With a VirtualBox installation of Windows 7 you can run the popular Microsoft operating system in a closed environment, which is a virtual computer device that can be given additional virtual hardware and used to test various dynamics.
One such dynamic is the 64 bit hardware setup, one which is certainly worth testing before full deployment in order to check for functional incompatibilities between the system you are currently using and Windows 7 64 bit. There are various applications and utilities that are not fully functional on this platform, so setting up a test environment is a useful idea that can help you test for issues and errors, research workarounds and make an informed decision about using the operating system.
Best of all, VirtualBox is free, so all of this research can potentially be done without additional financial outlay. However, not all computers are suited to running virtual 64 bit environments; it shouldn’t take you too long to work out if your VM is suitable for your physical hardware as errors will occur should you attempt to install an unsuitable operating system.
How the Error Appears
If you have VirtualBox set up on your computer and you attempt to install Windows 7 64 bit, unless you have the correct hardware, an error will occur. Typically, the error will generate after you see the “Windows failed to start" message, with the following message listed at the bottom of the screen:
Attempting to load a 64-bit application, however this CPU is not compatible with 64-bit mode.
This is the important bit. If you believe that your CPU is compatible, then you will need to continue reading in order to find out how to allow virtualization of this operating system to be achieved. However, if your host computer hardware is quite old and you don’t have a multicore 64-bit CPU (for instance an Intel Core Duo, Core i3 or higher or an AMD Phenom II) then your attempts to install this version of the operating system will be doomed to failure.
Activating 64-Bit Support on Your Computer
In order to have your 64-bit compatible physical computer behave in the right way and allow you to enjoy installing and using a virtual Windows 7 machine, you will need to check your computer BIOS for the correct setting, and activate it.
This is best done by restarting your PC and as the motherboard manufacturer splash screen appears, tapping DEL or F2. If this doesn’t open the BIOS, look out for some text that indicates the correct key. It should appear on screen for a second or two before Windows starts to load.
Once logged into the BIOS, you will need to look for VT-x or AMD-v, depending on your processor type, and activate this. These refer to the hyper-v technology that allows virtualization on your CPU and motherboard.
You might find that this setting is locked. This can happen if the manufacturer of your computer has locked the BIOS. It is possible that flashing the BIOS can resolve this; however you might choose to find a different solution.
VirtualBox Forums, http://forums.virtualbox.org/viewtopic.php?f=6&t=17782
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