"Upload complete" displays but code doesn't execute--problem with USB?

I am trying to upload code to an Arduino Uno to use with the MeArm robot kit. When I press "Upload", the IDE displays "Upload complete", but the Arduino does not execute the code and the robot does not move.

This may be related to a problem with USB detection--I have checked Device Manager and the device in the COM port does not register as an Arduino. However, the Uno still has power and can run the basic "Blink" sketch.

I have also tried switching to another Uno and to a Pro, and switching the USB connector cable, but the same problem has appeared every time.

Has anyone else encountered this issue? Is there a known fix?

Please provide a schematic diagram how you have wired everything; photo/scan of hand-drawn one is fine.
Please provide your code (between code tags [code] and [/code]; if it's too big, attach it).

If the blink sketch works, you have a wiring, power or code problem; you can try a simple serial test program to test communication.

E.g. the below will echo what you type in serial monitor.

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  if(Serial.available() > 0)
  {
    Serial.write(Serial.read());
  }
}

Here is the code:

#include <Servo.h> 
 
Servo middle, left, right, claw ;  // creates 4 "servo objects"
 
void setup() 
{ 
  Serial.begin(9600);
  middle.attach(11);  // attaches the servo on pin 11 to the middle object
  left.attach(10);  // attaches the servo on pin 10 to the left object
  right.attach(9);  // attaches the servo on pin 9 to the right object
  claw.attach(6);  // attaches the servo on pin 6 to the claw object
} 
 
void loop() 
{ 
  middle.write(90); // sets the servo position according to the value(degrees)
  left.write(90); // does the same
  right.write(90); // and again
  claw.write(25); // yes you've guessed it
  delay(300); // doesn't constantly update the servos which can fry them
}

And here is a diagram of the MeArm wiring, which I have checked several times to make sure I have followed exactly.

No real knowledge of Servos and steppers. Have you tried with a single servo (disconnect the others).

If you can upload, there is no USB issue. I have a Sparkfun RedBoard that also does not register as an Uno; reason (as far as I know) is that it uses the FTDI chip for the USB communicastion which is generic.