Email alerts - under ‘CMS Maintenance and Email Alerts’ here Xibo CMS Post-Installation Setup Guide
As Dan has mentioned, request screenshot function, which also can be configured to take a screenshot of your display each x minutes and send it to the CMS.
On displays page -> request screenshot it will take one screenshot and send it to the CMS
On display settings page -> edit display profile assigned to your device -> advanced tab -> screenshot interval if you want to configure it to take the screenshot each x minutes.
It can be also used to send the status window information, please see ‘second option’ here - Getting the Player Status
On top of all that, as we already mentioned there are a lot of free/paid software to gain remote access to Windows PC.
Side note, it would be good to update to 1.7.8 both CMS and Windows clients.