i dont know if this is in the right place but i need some help i have a prusa i3 3d printer and im having problems connecting it to my computer to use repetier or pronterface. i can send stuff to it using arduino. i have made sue the baud rate and the come port all match but still nothing i am useing windows 7 64 bit please help
Where have you set the baudrates?
One is in your firmware, the other in either Repetier (or Pronterface).
Only one device can use a COM port (Virtual in this case) at one time, have you closed the Arduino software?