1. First you must change some option in BIOS.
The Way  Press F2 select Processor Settings , Enable Virtualization Technology .
2. Setup ESXI5.0
- Mount the vSphere 5.0 cd-rom in the host
- Boot from CD-Rom drive
.
- Choose: ESX-5.0.0 Installer in the menu
 
- Press: Enter to continue the installation
- Accept the EULA – Press: F11
 Choose Disk
 
Choose keyboard layout
   
 Set root password
    Gathering additional system information.
   
  Start install
 
Installation Complete.
ESXi 5.0.0. has been successfully installed.
Remove the installation disc before rebooting
Reboot the server to start using ESXi 5.0.0