INPUTS activating uncontrollably on PC

Hello!

I have set up my diecimilla board with 15 INPUTs that will react to buttons being pressed. I have noticed that on some days when I set the arduino on my pc, it starts to recongnized INPUTS being activated when nothing is even plugged into the board. I do have the proper drivers installed, and like I said, some days it works like a dream and others it doesn't. It should be noted too, that I have a mac and it runs fine on it, but I would prefer to run it on my PC :).Has anyone else experienced this problem? Below is the code if am working with. Thanks!

andrew

int analogInput0 = 0;
int digitalInput0 = 0;
int digitalInput1 = 1;
int digitalInput2 = 2;
int digitalInput3 = 3;

int analogInput1 = 1;
int digitalInput4 = 4;
int digitalInput5 = 5;
int digitalInput6 = 6;
int digitalInput7 = 7;

int analogInput2 = 2;
int digitalInput8 = 8;
int digitalInput9 = 9;
int digitalInput10 = 10;
int digitalInput11 = 11;

int value_ali1 = 0;
int value_ali2 = 0;
int value_ali3 = 0;
int value_ali4 = 0;
int value_ali5 = 0;

int value_dan1 = 0;
int value_dan2 = 0;
int value_dan3 = 0;
int value_dan4 = 0;
int value_dan5 = 0;

int value_and1 = 0;
int value_and2 = 0;
int value_and3 = 0;
int value_and4 = 0;
int value_and5 = 0;

void setup(){

  pinMode(analogInput0, INPUT);
  pinMode(digitalInput0, INPUT);
  pinMode(digitalInput1, INPUT);
  pinMode(digitalInput2, INPUT);
  pinMode(digitalInput3, INPUT);
  
  pinMode(analogInput1, INPUT);
  pinMode(digitalInput4, INPUT);
  pinMode(digitalInput5, INPUT);
  pinMode(digitalInput6, INPUT);
  pinMode(digitalInput7, INPUT);
  
  pinMode(analogInput2, INPUT);
  pinMode(digitalInput8, INPUT);
  pinMode(digitalInput9, INPUT);
  pinMode(digitalInput10, INPUT);
  pinMode(digitalInput11, INPUT);
  
  value_ali1 = analogRead(analogInput0);
  value_ali2 = digitalRead(digitalInput0);
  value_ali3 = digitalRead(digitalInput1);
  value_ali4 = digitalRead(digitalInput2);
  value_ali5 = digitalRead(digitalInput3);
  
  value_dan1 = analogRead(analogInput1);
  value_dan2 = digitalRead(digitalInput4);
  value_dan3 = digitalRead(digitalInput5);
  value_dan4 = digitalRead(digitalInput6);
  value_dan5 = digitalRead(digitalInput7);
  
  value_and1 = analogRead(analogInput2);
  value_and2 = digitalRead(digitalInput8);
  value_and3 = digitalRead(digitalInput9);
  value_and4 = digitalRead(digitalInput10);
  value_and5 = digitalRead(digitalInput11);

  beginSerial(9600);
}

void loop(){  
  if(value_ali1 >= 512){
    Serial.print('A');
  }
  if(value_ali2 == 1){
    Serial.print('B');
  }
  if(value_ali3 == 1){
    Serial.print('C');
  }
  if(value_ali4 == 1){
    Serial.print('D');
  }
  if(value_ali5 == 1){
    Serial.print('E');
  }
  
  if(value_dan1 >= 512){
    Serial.print('F');
  }
  if(value_dan2 == 1){
    Serial.print('G');
  }
  if(value_dan3 == 1){
    Serial.print('H');
  }
  if(value_dan4 == 1){
    Serial.print('I');
  }
  if(value_dan5 == 1){
    Serial.print('J');
  }
  
  if(value_and1 >= 512){
    Serial.print('K');
  }
  if(value_and2 == 1){
    Serial.print('L');
  }
  if(value_and3 == 1){
    Serial.print('M');
  }
  if(value_and4 == 1){
    Serial.print('N');
  }
  if(value_and5 == 1){
    Serial.print('O');
  }
  delay(1000);
}

turn on the internal pullups on all of the switch sensing pins. For instructions on how to do this & what this means, read the pullup resistor sections here:

http://www.arduino.cc/en/Tutorial/DigitalPins & here:
http://www.arduino.cc/en/Tutorial/AnalogInputPins