Virtualization Technology ( VT-x and AMD-V )
First of all VT-X and AMD-V offer the same technology but come from two different processor Manufacturers. Virtualization Technology allows a program running under an operating system to obtain full control of the CPU. If your VT is not enabled, then emulators like NOX can’t run at full speed because they are running with only 1 Core. In addition, not any CPU has Virtualization Technology, so you can check if your CPU supports this feature.
Intel
For the Intel chipset, download the Intel® Processor Identification Utility program, install it and run it. Go to the tab CPU Technologies and check at the Supporting Advanced Intel Processor Technologies if the Intel(R) Virtualization Technology is Yes. If it is yes, then your CPUs support the VT-x.

AMD
For the AMD chipset, download the AMD Virtualization™ Technology and Microsoft® Hyper-V™ System Compatibility Check Utility. It is a .zip file, extract it to a folder, and run amdvhyperv.exe with Administrator Rights. Check if it shows the successful results, “This system is compatible with Hyper-V“. If it shows that message, then CPU’s support the AMD-V.

How to enable Virtualization Technology
To enable VT you need to Restart or Power On your PC. When the first logo of your screen appears, immediately press the F2 or the DEL key two or three times to enter the BIOS.
Go to Advanced Settings and select the option Virtualization Technology: Disabled to Virtualization Technology: Enabled
From Motherboard to Motherboard your environment settings may be different, but it is kinda always the same sequence. Search for tab Advanced BIOS Features / Chipset / System Security, open the tab, find and enable VT-x or AMD-V Hardware Accelerator.
Save the settings in the bios ( You can press the button F10 to save the settings in the bios ) and restart your PC.

Disable Hyper-V
If your Hyper-V is enabled in Windows, you must disable it. Hyper-V uses Virtualization Technology and probably won’t allow you to use more than 1 app.
Open CMD ( Command Prompt ) and run it as administrator. Write this
dism.exe /online /Disable-Feature: Miscrosoft-Hyper-V
and hit enter to disable this Feauture!