Can I still use an end-point, if the device has crashed and cannot be used anymore?
Yes. In case your device crashes due to hardware or software problems, and you have to set up a new device, the TeamViewer ID of the new device will be different.
Therefore, just remove the old TeamViewer ID/device from your Computers & Contacts list. Log in again, add the new device to your Computers & Contacts list and activate ITbrain for the end-point.
The number of used end-points remains unchanged.