hardware virtualization

i check VT with SecurAble and result is that VT is Locked Off:

citation:

This processor's advanced hardware support for virtualization has been disabled and "locked off" by some external influence - most likely by this system's BIOS as the system was booting. Since enabling hardware virtualization will allow faster and more secure virtual machines and their hosting operating systems to run at 100% full speed, you may wish to poke around in your system's BIOS to see whether you're able to find any references to "hardware virtualization" or "VMX", etc.

I'm not sure where you received the information that the T4300 supports VT, because Intel's own datasheet says that it does not:

http://ark.intel.com/Product.aspx?id=37253

The reason you do not see the option (i.e., it's locked off) is because your CPU does NOT support it.  Upgrade to a socket P CPU that does support VT and you'll find the option appears.

If you don't see the option, it means your CPU doesn't support virtualization.  What model CPU (T.... P..., etc.) do you have? 

You'd need to upgrade your CPU to one that does support VT - then the option will appear.

my CPU is pentium dual-core t4300 2.10Ghz, and  it  supports VT

ejn63, thank you, it was my mistake to decide that T4300 supports VT