This CPU is VT-capable, but VT is not enabled

尝试虚拟的操作系统是Oracle的Enterprise Linux 4 for X86-64，因此在系统选项中选择了Other Linux 64bit，尝试系统后系统报错：

This CPU is VT-capable, but VT is not enabled (check your BIOS settings).
You have configured this virtual machine as a 64-bit guest operating system. However, this host's CPU is not capable of running 64-bit virtual machines or this virtual machine has 64-bit support disabled.
For more detailed information, see

点击确定，屏幕显示错误信息为：

Your CPU does not support long mode. Use a 32bit distribution.

对于这种情况，需要设置BIOS将Inter Virtualization Technology设置为ENABLE，然后重启系统，就可以了。

如果BIOS设置了没有类似的设置，那么系统就无法虚拟64位的系统了。