VirtualBox not allowing me to install a 64bit OS

[jromie0924]

This has been an issue for a while now - I cannot get virtualbox to allow me to install a 64-bit OS. It only provides an option for 32bit operating systems.
I have followed the countless other forums where they say that all I need to do is enable Intel Virtualization Tech., VT-x, vt-d, etc. This has not been successful.

I just upgraded to 4.3.22, but this has been an issue with previous versions as well.
The two computers I would like to run VirtualBox on are as follows:

- Asus N56JR laptop with Intel Core i7 4500HQ CPU, Windows 8.1 64bit
- Custom build PC with ASRock Z87 Extreme-4 Motherboard, Intel Core i5 4670k CPU.

If anyone has any suggestions to help stear me in the right direction, that would be great. I can provide files, etc.

Thanks!

[Perryg]

FAQ: I have a 64bit host, but can't install 64bit guests.