Sketches will not run on Arduino Uno

I was posting on the wrong site & getting limited/unsatisfactory responses.

I am using an Arduino uno. I have set the board to Arduino Genuino Uno com port 3, with no pin connections to anything. Prior to this I have used the board on considerably more complex programs & it worked perfectly, now it won't work on any sketches, even this simplest of all. Here is the code directly from the menu & error code:

*/

// the setup function runs once when you press reset or power the board void setup() { // initialize digital pin LED_BUILTIN as an output. pinMode(LED_BUILTIN, OUTPUT); }

// the loop function runs over and over again forever void loop() { digitalWrite(LED_BUILTIN, HIGH); // turn the LED on (HIGH is the voltage level) delay(1000); // wait for a second digitalWrite(LED_BUILTIN, LOW); // turn the LED off by making the voltage LOW delay(1000); // wait for a second

}

Arduino: 1.8.5 (Windows 10), Board: "Arduino/Genuino Uno"

Sketch uses 928 bytes (2%) of program storage space. Maximum is 32256 bytes. Global variables use 9 bytes (0%) of dynamic memory, leaving 2039 bytes for local variables. Maximum is 2048 bytes. avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x30 avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x20 avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x30 avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x20 avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x30 avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x20 avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x30 avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x20 avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x30 avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x20 An error occurred while uploading the sketch

This report would have more information with "Show verbose output during compilation"

option enabled in File -> Preferences.

I ran the loop back test, and it worked perfectly. Any suggestions?

avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x20

This means the problem is not with your sketch. The IDE does not communicate with the board. First things to try: - restart PC - try another USB port - try another USB cable - try another Arduino if available

Which ever port the Arduino shows up in Device Manager is the USB port to use in the IDE.

I had to switch to Com 10 & it worked. From now on I will use the troubleshooting list then the loop back test before bothering people on this list.

Thanks for your help, guys!