Problems with Arduino Due

Hello!

Recently we bought a Arduino Uno which is working like a charm.
The only problem is the speed, so we decided to get a faster/stronger chip.
We bought the Arduino Due (rev3) but can't seem to get it to work properly.

When connecting the Due to the Programming port nothing happends. No port in Device manager shows up.
When connecting the Due to the Native port we get a unknown device. When pressing reset it changes to (for example) COM5 and is called Bossa. When trying to upload ''Blink'' it resets the CPU. The device changes to COM6 in device manager and is now called Arduino Due. When trying to do something after that the device resets/loses connection and disapears... Am I missing something or is my Due broken?
Thanks in advance,

Kris