COM Port not working when no other apps open in Arduino Software on Windows 10

If this helps any, here’s the exact error message:

This report would have more information with
“Show verbose output during compilation”
enabled in File > Preferences.
Arduino: 1.0.6 (Windows NT (unknown)), Board: “Arduino Uno”
Binary sketch size: 1,194 bytes (of a 32,256 byte maximum)

processing.app.SerialException: Serial port ‘COM3’ already in use. Try quiting any programs that may be using it.

at processing.app.Serial.(Serial.java:171)

at processing.app.Serial.(Serial.java:77)

at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:77)

at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:175)

at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)

at processing.app.Sketch.upload(Sketch.java:1666)

at processing.app.Sketch.exportApplet(Sketch.java:1622)

at processing.app.Sketch.exportApplet(Sketch.java:1594)

at processing.app.Editor$DefaultExportHandler.run(Editor.java:2382)

at java.lang.Thread.run(Thread.java:619)

processing.app.debug.RunnerException: Serial port ‘COM3’ already in use. Try quiting any programs that may be using it.

at processing.app.debug.Uploader.flushSerialBuffer(Uploader.java:101)

at processing.app.debug.AvrdudeUploader.uploadViaBootloader(AvrdudeUploader.java:175)

at processing.app.debug.AvrdudeUploader.uploadUsingPreferences(AvrdudeUploader.java:67)

at processing.app.Sketch.upload(Sketch.java:1666)

at processing.app.Sketch.exportApplet(Sketch.java:1622)

at processing.app.Sketch.exportApplet(Sketch.java:1594)

at processing.app.Editor$DefaultExportHandler.run(Editor.java:2382)

at java.lang.Thread.run(Thread.java:619)

Could you help me?

Find the app that has the serial port open and shut it down.