Uploading issue

Arduino: 1.8.9 (Windows 8.1), Board: “Arduino/Genuino Uno”

Sketch uses 7582 bytes (23%) of program storage space. Maximum is 32256 bytes.
Global variables use 274 bytes (13%) of dynamic memory, leaving 1774 bytes for local variables. Maximum is 2048 bytes.
avrdude: ser_open(): can’t open device “\.\COM5”: The system cannot find the file specified.

Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.

This report would have more information with
“Show verbose output during compilation”
option enabled in File → Preferences.

Most probably your Uno isn't actually on COM5.

Select the correct port using Tools/Port in the IDE. There's often only one that isn't greyed out...that's the one you want.