Power Supply Questions

No, Vcc is the correct way to get 5v out. You can't get all that much current out, since it has to dissipate the energy as heat and it's a rice-grain sized part (if you need more current, use an external voltage regulator - either linear (like a 1117-series) or a dc-dc step-down converter for higher current and greater efficiency, at a cost of higher standby power consumption and greater complexity (search ebay for dc-dc step down in industrial and test equipment - you'll get results starting at about $1 counting shipping)

Please post a schematic showing all of the connections. A picture of a neat hand drawn schematic is fine. We need to see exactly how everything was wired. Also, what kind of screen? Post link to the product page you got it from.