"SEMAPHORE TIME OUT PERIOD HAS EXPIRED" PROBLEM UPLOADING PROGRAM

Hello, Please help. I have a problem in uploading my program into the arduino board. It was working properly for the past few month. Suddenly this error has come up. Please help.

The error message

Arduino: 1.6.13 (Windows 10), Board: "Arduino/Genuino Uno"

Sketch uses 928 bytes (2%) 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 semaphore timeout period has expired.

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.

Do you have the correct COM port selected? Check tools -> port. Com ports get numbered differently if plugged into a different USB port (for example).

Yes, I have the correct port number selected.