Is my Arduino fried?
As noted in the previous answer, being able to upload a new sketch indicates an Arduino is ok in general – in particular has a functioning CPU – but of course that does not test all features.  For example, individual inputs and outputs can be damaged.

You can easily change your sketch so that it drives some range of outputs, as shown below.  Thereafter, try moving the red wire (that now connects on 13) to some other of the outputs in the selected range.  

enum { LedLo=2, LedHi=20}; // Set lo and hi limits of range

void setup() {
  for (int led=LedLo; i &lt;= LedHi; ++i)
    pinMode (led, OUTPUT);
}

void loop() {
  for (int led=LedLo; i &lt;= LedHi; ++i)
    digitalWrite(led, HIGH);
  delay(4000);
  for (int led=LedLo; i &lt;= LedHi; ++i)
    digitalWrite(led, LOW);
  delay(4000);
}