In order to take advantage on the full capabilities of GiD, you need to register a password that can be obtained from www.gidhome.com. From this site you can obtain a permanent or temporary password.
If there is some USB memory stick plugged then GiD will show a window with a list to allow the selection of this device (portable licence) or the local machine (local licence). Highlight the one you want and press Select.
The password must be typed in the window shown below.
If you have previously registered your current copy of GiD, the password can be reloaded by clicking the icon and selecting the folder where the old password is.
In case of floating licences the 'machine and password' are replaced by the 'IP' of the 'passerver' password server.
After registering either a permanent or temporary password you will be able to generate and postprocess an unlimited number of nodes and elements.
Note: To save the password to disk (in order to be remembered next times) it could be necessary to allow GiD to be run 'As administrator'.