Happy New Year :)

Guys on the CSim 737-200 I am halfway through a flight and a darn warning horn is giving me the headache.
I am on autopilot with Aileron, Elevator, and heading hold activated.

The 'Stabiliser Trim Light' (On the center console just below the main throttle settings) is on and flashing and the darn warning horn is going off all the time.
I can't seem to find out how to reset it / shut it up.
Tried disconnecting AP and clicking YAW off and on. Tried trimming rudder / Ailerons.
Nothing seems to work.
Thanks for any advice.
Terry.

P.S. I asked here as I can't start new topic yet. Am a newbie  ;)