You need to have hardware virtualization enabled if you want to run Windows 8 in Virtual Box

If your processor does not support Virtualization Technology then you can't run Windows 8 in Virtual Box....you will get a black screen of death. In order to find out if your CPU supports hardware Virtualization Technology you can download the Intel Processor Identification Utility here http://www.intel.com/p/en_US/support/highlights/processors/toolspiu/



Run it and look if Virtualization Technology is enabled...see the bottom of this picture

if it is enabled then you need to turn it on in your BIOS, to see how to configure BIOS, go to this page http://www.microsoft.com/windows/virtual-pc/support/configure-bios.aspx

After BIOS has been configured, you need to do a reboot, shut down, wait about 10 seconds and then start up again.

Now you are ready to make the changes in Virtual Box
Click on settings, then system and then on the motherboard tab, click on Enable IO APIC

On the Processor tab, click on Enable PAE/NX

Finally on the Acceleration tab, click on both Enable VT-x/Amd-v and Enable Nesting Paging

Now you are all set...have fun