- Login to control panel.
- Click VNC.
- Click on HTML5 Client.
- Click Start, and then click Command Prompt.
- For Windows 2012 Type slmgr.vbs /rearm and then press ENTER.
- Restart the server through control panel or through windows menu.
- For Windows 2008 Open Server Manager, Click on Activate Windows then Click Next and finish the dialogue box.
- Your trial will be activate now.