By default VMware ESXi 5.0 (VMware vSphere Hypervisor) installs in 60 days Evaluations mode.

Licence key can be obtained for free from www.vmware.com. To update the license key perform following:

• Login to your host unsung VMware vSphare client
  
• Change to Configuration tab click on Licensed Features and click Edit
  
  
• Select Assign a new license key to this host and click on Enter Key
  
  
• Enter the key and click OK