Win7 installation on VirtualBox

Solution 1:

You must enable hardware virtualization in BIOS

Source

Solution 2:

All virtualization solutions nowadays attempt to use hardware assisted virtualization, instead of software emulation solutions (binary translation). One of those hardware virtualization technologies is Intel's virtualization technology(VT-x). Although AMD supports its own virtualization technology (AMD-V), the basic processor virtualization extensions are named after Intel's solution. I would not like to go any further on virtualization theory and such, if you would like to read, this wikipedia article is highly informational.

How to enable VT-x

There are two configurations you should perform if you would like to enable hardware assisted virtualization. Those are:

• First of all, make sure that you have enabled Virtualization extensions in your hardware.
• After you have done so, Enable vt-x in the virtual machine configurations. To do so: Right click on a virtual machine in the Virtual Box user interface -> Settings -> System -> Acceleration -> Enable Vt-x/AMD-v