How to unhide hidden pins in proteus?
In order to see the hidden pins and the nets they are connected to you should double click the microcontroller and then click the hidden pins button.



There is no need to unhide the power pins, just connect the 5v regulator output to the Vcc net and the regulator ground to a GND net. 

To place a Vcc terminal (the upwards pointing triangle) select the terminals menu, place a POWER terminal and double click it to select Vcc net. For the ground terminal just place a GROUND terminal, it's already connected to the GND net.



Then when you open the ARES layout you will see the following connections from the regulator to the microcontroller power supply pins