The USB can only give you MAX 500mA, if the FTDI and the Atmega chip draw a total of 150mA(and this is being conservative) and the lcd another 100mA, 16leds drawing 20mA each, will give a total of 150+100+(16*20)=570mA, more than the maximum allowed by the USB specs, they should shutdown when there is overcurrent but they may not do that and just burn you one port or your motherboard usb hub.