Hi, this same thing happened to me (four to three prong, plugged it in to check not thinking , I didn't turn off the breaker, now I know),. I went ahead and completed the install with the new power cord, and when I turned the breaker back on, the dryer just beeps but will not turn on or show anything on its face. I don't think there's anything wrong with the dryer since it was not plugged in when I went to plug in this new cord. Do you think it's the cord that is messed up and needs replacing