vt-x is disabled in bios for all cpu modes

[farshadff]

hi good day ,

i did as instruction says but when i run vagrant up i get this error after a while :
 1: from /usr/share/rubygems-integration/all/gems/vagrant-2.0.2/lib/vagrant/util/retryable.rb:17:in `retryable'
/usr/share/rubygems-integration/all/gems/vagrant-2.0.2/plugins/providers/virtualbox/driver/version_5_0.rb:714:in `block in start': There was an error while executing `VBoxManage`, a CLI used by Vagrant (Vagrant::Errors::VBoxManageError)
for controlling VirtualBox. The command and stderr is shown below.

Command: ["startvm", "8466b721-19f8-42d0-93f7-8238ae917a78", "--type", "headless"]

Stderr: VBoxManage: error: VT-x is disabled in the BIOS for all CPU modes (VERR_VMX_MSR_ALL_VMX_DISABLED)
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component ConsoleWrap, interface IConsole
There was an error while executing `VBoxManage`, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.

Command: ["startvm", "8466b721-19f8-42d0-93f7-8238ae917a78", "--type", "headless"]

Stderr: VBoxManage: error: VT-x is disabled in the BIOS for all CPU modes (VERR_VMX_MSR_ALL_VMX_DISABLED)
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component ConsoleWrap, interface IConsole

i enabled the option in graphic ui but again the same error