Help needed with errors while uploading the program.

I bought an Arduino UNO board hours ago and I'm really a beginner in this.
Directly getting to the problem I'm facing, I would like to know what to do when I get errors uploading the simplest program i.e. "blinker"

I wrote a "blinker" program using IDE (v1.8.5) as follows:

const int LED = 2;
void setup() {
pinMode (LED, OUTPUT);
}
void loop() {
  // LED gets ON for 1 sec and gets OFF for 1 sec:
digitalWrite(LED, HIGH);
delay(100);
digitalWrite(LED, LOW);
delay(100);
}

when clicked on verify I get this messege on messege panel:
"Sketch uses 926 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."

And when I click on upload, after some time I get a message :
"avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x8a
Problem uploading to board.
See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions."

I read all the forums but that didn't help me
additional information as follows:

  1. I have a windows 7 PC
  2. In IDE>ports>serial ports this option is greyed out.
  3. In device manager>ports (COm & LPT) I see only one option "Communications Port (COM1)"
  4. There is no option mentioning "unknown pots" or "Arduino UNO" in Device manager.
  5. When Arduino is connected to my PC via USB cable, a greenish-yellow light gets ON and a completely different orange light keeps blinking next to the D13 pin. I don't know what's that for or why it keeps blinking.
  6. I tried to plug the USB in different ports but still, I see only "COM1" in IDE>tools>port section and serial port option greyed out.

I would be very happy if this problem gets resolved since I'm really excited about all this stuff.