Teddy0483 wrote:So, it may be my power supply? I have a 5v 2000mA PSU. From the sounds of it, that is not nearly enough.
In most cases, 2A will be plenty enough current. For example, I can run a Pi2 with the 7" display powered from my laptop's USB port. Yes the display does show the rainbow square top right, but it is working fins apart from that. I am powering the display from the pi via the supplied DuPont cables to the GPIO port's +5/GND lines, with laptop USB cable going direct to the pi.
I suspect you either have a genuine fault, or the cables are not making good contact. Also beware that the '5v 2000mA PSU' may not be accurate.
If you have a voltmeter you may be able to measure the voltage on the pi - if it is considerably lower than 5v it may be a sign that the total current used is more than the PSU can supply.....
Texy
Various male/female 40- and 26-way GPIO header for sale here ( IDEAL FOR YOUR PiZero ):
https://www.raspberrypi.org/forums/viewtopic.php?f=93&t=147682#p971555