My first Teensy 3.0 "died"...
Today I received two new Teensy 3.0 boards. If I plug one of them to an USB-Port it is recognized as "serial port" and the board starts working. But when I want to flash a new sketch it stopps working, but it will not be programmed. When I press the button, nothing happens. In the system-properties-panel of my Win7 64bit it is recognized as "Unkown Device". I tried several USB-Ports and different cables...nothing!
When I restart the PC after pressing the teensy-button and try to programm it works for only one time! Trying to re-programm doesn't work.
Re-installing the drivers --> same problems!!

Has someone any idea?