You have configured this virtual machine to use a 64-bit guest
operating system. However, 64-bit operation is not possible. This
host is VT-capable, but VT is disabled. This is usually because VT has
been disabled in the BIOS/firmware settings or the host has not been
power-cycled since changing this setting. Please: (1) Verify that the
BIOS/firmware settings enable VT and disable ‘trusted execution.’ (2)
Power-cycle the host, if either of these BIOS/firmware settings have
been changed. (3) Power-cycle the host, if you have not done so since
installing VMware Workstation. (4) Update the host’s BIOS/firmware to
the latest version. For more detailed information, see
http://vmware.com/info?id=152. Continue without 64-bit support?
翻译过来是
您已经配置此虚拟机使用64位客户操作系统。然而，64位操作系统不可用。此主机具有虚拟化支持能力的，但虚拟化技术被禁用。
这通常是因为虚拟化技术已经在BIOS /固件设置或禁用或主机没有权限改变此设置。 请：
（1） 验证 BIOS/固件设置 VT 启用和禁用 ‘trusted execution.’
（2） 如果更改了这些 BIOS/固件设置 重新启动主机电源。
（3） 安装 VMware Workstation，重新启动主机.
（4） 更新到最新版本的 BIOS/固件。
更多详细信息请参阅 http://vmware.com/info?id=152 。
不支持 64 位的情况下继续吗？

我怀疑是安装Ubuntu后系统BIOS默认关闭了虚拟化的功能.所以
开机F12->BootMenu->->Config->CPU->
将Intel(R) Virtualization Technology和Intel(R) VT-d Feature选为Enabled
重新启动虚拟机,正常了!