The following is a part of a post that I copied from an older thread relating to your problem. I can't say for sure that it will help you, but you might give it a try.
"Actually very easy to turn off the alarm! The user guide is pretty lame, but a couple of minutes with the remote in hand and waalaa, alarm turned off. I had inadvertantly turned it on when trying to set a wake up alarm. Turn the radio on and put on the noaa channel, press the alarm button on the remote and watch the display (there is a little speaker/horn icon). Once to turn on and once to turn off."
Peace
Dave