I have issues with my server 2008

I have installed Server 2008 in my Computer. I need to execute virtual machine as I have only one computer. I have installed and set up DCPROMO to set up the role of DC. I have added hyper-v role after the reboot. It was using virtual network which was created automatically. I have installed VHD and created virtual machine.
I have installed the operating system from DVD. It looks like everything is fine. However, when I am click to start it an error message is displayed. The message displayed is ‘It is failed to initiate the virtual machine. I have set up the BIOS to activate the virtualization.
Please help me to get out of this problem.
Thanks in advance.
