I've got an Arduino Micro and used it for a few weeks, after that it stopped working 
. When I plug my Arduino Micro into the Computer, it executes the Code, but the RX LED is on and I can't connect to upload code. Sometimes I can connect, but when I click "Upload", it compiles the Code and says "Uploading...", but nothing happens. I clicked on "Upload" and left my Computer on for hours, but it didn't work. BTW I've got an Arduino Mega too, but that one works fine with same computer and software...
If you enable File > Preferences > Show verbose output during: > upload you will be able to see the progress of the upload in the black console window at the bottom of the Arduino IDE window. You might need to resize or scroll up to see it all. If you copy and paste the full contents of the console window in a reply here, it might provide some information that will make it easier for us to help you.
Are you sure COM8 is the correct port for your Micro? You should see it listed in the Tools > Port menu, though it might be identified as a Leonardo instead of a Micro.
Adding to @pert's reply
What happens when you tap the reset button on the board when PORTS {COM8, } / {COM8, } => {} is showing?
Also please check in device manager what happens when you connect the Micro and when you reset the Micro using the reset button (does not have to be during upload). Can't check at this moment but you should see a com port appear with the name Micro and when you press the reset button it should change to Micro Bootloader and a different port and after a while (8 seconds?) fall back to Micro.