Make sure you have not enabled the "loop in" function on the virtual DJ deck your song is playing on. If you have accidentally activated a loop, press the "loop out" button to stop the song. Remember, the song will stop as soon as the loop as finished. If you are performing with your software, this may create an awkward transition.
Lower the master volume control on the deck you are using to temporarily mute the track. This may be in your best interest if you plan on continuing to use the second deck while you discover and correct the problem on the malfunctioning deck.
Force the software to quit if you cannot find any process within the program that is causing the music to continue. On Macintosh computers, click the "Force Quit" button in the apple menu. If you are using a Windows computer, pressing "alt-f4" will typically close the program. Although this will cause all music to stop completely, it will allow you to restart the program quickly and continue performing.
Check the Sonique website to ensure that you are using a properly updated version on the Virtual DJ plugin. Outdated software versions can create problems within other applications. Patches are often released to remedy any bugs or flaws within the software. Downloading an updated version of the plug in may correct any problems with the Virtual DJ software.