I have an Intel I5 processor and an Asus B85M-E motherboard. The only setting in the BIOS concerning VT-x says "Enabled". I am running the 64 bit version of Windows 7. But Virtual Box says that VT-x is not supported on this hardware. Has anyone else had this problem?
I have the same morherboard and core i5 4400 proc and I had the same issue. I solved it by disabling Hyper-V. Its not possible to run Hyper-V alongside Virtualbox.