user19700: EDIT :
I have plenty of weird bugs. I will open another thread, and come back to this one when I have better understanding, rather than completely modify this one halway through. Sorry to every answerer for my electronic incompetence which led me to ask the wrong questions; I hope the other thread makes more sense.
I have recently exhumed an arduino from a cupboard, and can't seem to make even a blinking LED circuit work correctly.
Here's the sketch :
void setup() {
  pinMode(9, OUTPUT);
}

void loop() {
  digitalWrite(9, HIGH);
  delay(1000);            
  digitalWrite(9, LOW);   
  delay(1000);              
}

This has been tried without the circuit, on pin 13, using the onboard LED, and it worked.
However, using the following circuit, it did not result in a blinking LED, using several pins (8, 9, 12, 13) and LEDS.
May I assume the arduino is fried?
Here is a thumbnail of the circuit :  

user521: Here's a guide posted by Nick Gammon for checking if your Arduino is bricked Is My Arduino Bricked ?

19700: <p>EDIT :</p>

<p>I have plenty of weird bugs. I will open another thread, and come back to this one when I have better understanding, rather than completely modify this one halway through. Sorry to every answerer for my electronic incompetence which led me to ask the wrong questions; I hope the other thread makes more sense.</p>

<p>I have recently exhumed an arduino from a cupboard, and can't seem to make even a blinking LED circuit work correctly.</p>

<p>Here's the sketch :</p>

<pre><code>void setup() {
  pinMode(9, OUTPUT);
}

void loop() {
  digitalWrite(9, HIGH);
  delay(1000);            
  digitalWrite(9, LOW);   
  delay(1000);              
}
</code></pre>

<p>This has been tried without the circuit, on pin 13, using the onboard LED, and it worked.</p>

<p>However, using the following circuit, it did not result in a blinking LED, using several pins (8, 9, 12, 13) and LEDS.</p>

<p>May I assume the arduino is fried?</p>

<p>Here is a thumbnail of the circuit : <a href="https://i.stack.imgur.com/plQLY.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/plQLY.jpg" alt="circuit picture"></a>  </p>
 521: <p>Here's a guide posted by Nick Gammon for checking if your Arduino is bricked <a href="https://arduino.stackexchange.com/questions/13292/have-i-bricked-my-arduino-uno-problems-with-uploading-to-board/13293#13293">Is My Arduino Bricked ?</a></p>
