Parameter estimation using ODE model

I wish to estimate three parameters A,B and C, from a second order differential equation

d^2(x)/dt^2= (A*z - x(1) - B*x(2)) / B*C;

I know z = 100%; ABC = Unknown; time = 0 : 14; %h x0 = 24.4;

I am new with matlab and I would be thankful if you can provide me with a solution.

I remember something about function handle, least square method and fminsearch, but confused now.

Thanks. Vicky.