activate GameObject dont work

hi, i have problem with activate gameobject, i try use GameObject.active = true;, GameObject.SetActive(true); and nothing work but when i write it with false it work, why is it? here is code what i use:

#pragma strict
 
static var speed = 0;
var particle : GameObject;

function Start () {

}

function Update () {
	particleSystem.startSpeed = speed /20;
	if(speed == 0) {
		particle.SetActive(false);
	}
	else {
		particle.SetActive(true);
	}
}

Remove the “else” statement. Instead, use “if”.

#pragma strict
 
static var speed = 0;
var particle : GameObject;
 
function Start () {
 
}
 
function Update () {
    particleSystem.startSpeed = speed /20;
    if(speed == 0) {
        particle.SetActive(false);
    }
    if (speed > 0){
        particle.SetActive(true);
    }
}