Most of the times, when Installing Hyper-V Role on Windows Server 2008 if the BIOS setting are not done properly it might give you the following errors when you restart the server.
Hyper-V launch failed; Either VMX not present or not enabled in BIOS.
Hyper-V launch failed; at least one of the processors in the system does not appear to provide a virtualization platform supported by Hyper-V.
In order to avoid such errors or fix the Hyper-V launch failed error, go through the following steps:
Step 1: Restart the Windows Dedicated Server 2008 and Login into the BIOS.
Step 2: Go to Advanced >> Advanced Processor Options. You will see something like the below image on your computer screen.
Step 3: Make sure the “Intel(R) Virtualization Technology” or “Intel VT” is Enabled in the BIOS settings.
Step 4: Once the Virtualization Technology is Enabled, simply reboot the server.
Once you reboot the server the Hyper-V will start successfully.