something gone really wrong?

Hi what can i do with this?

Arduino: 1.6.6 (Windows 7), Board: "Arduino/Genuino Uno"

Sketch uses 450 bytes (1%) of program storage space. Maximum is 32,256 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 2,039 bytes for local variables. Maximum is 2,048 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"
enabled in File > Preferences.

Except for the word file it pretty much tells you what's the problem... COM5 does not excist! Did you plug in the Arduino into another port then last time? Select the correct port under Tool -> Port

Select the com port corresponding to your Arduino board from the tools -> port menu.

The IDE always tries to use the last port number it used, but if you plug the arduino into a different usb port, or windows decides to change the number for no apparent reason, the number can change. If the com port isn't showing up even with Arduino plugged in, that implies a hardware or driver problem.