Garly, it sounds like the brake is engaged. If the saw will run but not rev up and the drive sprocket will not turn the kickback safety brake has engaged. Doesn't take much to make it lock up either, first time it happened to me i thought i broke my saw. And it took more than a couple of minutes for me to realize what had happened. To engage and disengage the brake push the knuckle guard foward away from the handle and then pull it back toward the handle until it clicks. If all else fails read the owners manual. HTH