tamper light on and control panel locked out optima xm burglar alarm?

I recently bought a house with the optima xm alarm system already in it(which has been working fine),until i started decorating.I accidentally nudged one of the sensors ,which instantly set the alarm off and highlighted the tamper light.After entering the code and then resetting the system i am no longer able to use the control panel.It appears to have locked itself out.So I nudged the sensor on purpose which set off the alarm again.This time i only put the code in.The buttons all made their beeping noises as usual but didnt actually do anything.I pushed reset button and it locked itself out again.After reading some other peoples problems i am thinking it may be the battery in the control panel but i'm not sure.Has anyone any idea's

mark
October 2007