I have a question regarding to this problems, what did I found that mostly PC with UEFI bios having problems detecting the vt-x. My current PC is unable to detect the vt-x but my old pc detect the vt-x that using legacy boot. I have tried looking for the answers in blogs, facebook groups and asking people about this problem but got nothing for the solution. Here is details about my old and new PC:
======-Intel® Pentium® Processor E5700
- BIOS is America Megatrend with legacy boot only
- OS Windows XP SP2
======-Intel® Core™ i5-3230M Processor
- BIOS is America Megatrend with secure boot
- OS Windows 8.1 Pro
Hopefully that Intel could do something to come out with solution for this kind of problem.