@Preben Alsholm

Yes !

op(S);
%;
op(S1);

did it , the first op(S) showed still the beta as parameter so after calculating the beta (1e step)  I reassigned S with the same command GenerateMatrix([eq1,eq2,eq3,eq4],[A,B,C,D]) assuming with beta known gives correct format,

and Solved ! :)

(That was tricky ...)

Thanks !!