I have an Arduino UNO and I'm using windows 10. I have already installed arduino-1.6.8-windows files on my computer. when i plug my UNO into my computer the "on" green led lights up but the computer doesn't do anything. when i go into my control panlle to see if the computer is reconizing it there is no COM PORT section or any UNKNOWN DEVICES. please help
Clone or original? If it's a clone, you might need the CH340 drivers; do a search on this forum.
Also it's often said that IDE 1.6.5 is the last solid release of the IDE. There are plenty of complaints about newer versions although I have not had issues with 1.6.6 in Win8.
Is it a real Uno or a clone? Check the markings on the chip near the USB connector - it will be either a 16u2 (like an official board), CH340G (google for and install the drivers for ch340g), or FT232 (occasionally, it may be something different). Some FT232's are counterfeit and don't work (google ftdigate).