Error during installing HAXM, VT-X not working

Even if you have enabled the Virtualization(VT) in BIOS settings, some antivirus options prevent HAXM installation.

For example: In Avast antivirus under Settings (parametres) tab > Troubleshooting (depannage), you should uncheck "Enable Hardware-assisted Virtualization" ("activer l'assistance a la virtualisation").

Now restart your computer and re-install the Intel's HAXM which can be found under ~SDK_LOCATION\extras\intel\Hardware_Accelerated_Execution_Manager. You can also manually download the standalone HAXM installer from Intel's website.

I had to enable it in my BIOS as shown below (for Asus):

I had exactly the same problem. And this is how I could fix it.

Step 1: Turn virtualization on in BIOS settings.

Step 2: Control Panel -> "Programs" -> "Turn Windows features on or off" (under "Programs and Features") and locate "Hyper-V", uncheck, reboot.

Step 3: In Avast->Settings->Troubleshooting. Uncheck "Enable hardware-assisted virtualization" & "Enable avast self-defense module"

Final step and the main:
Go to MyPC / right click / Advanced System Settings / Advanced / In Performance click SETTINGS / Data Execution Prevention and enable DEP for all programs and services.

The last step helped me to solve this problem. Hope you too.