Second order coupled differential equations

Question

I am trying to solve two coupled ordinary differential equation.

$x''+Ax'+By'+Cx+Dy=U$ ;

$y''+Ex'+Fy'+Gx+Hy=V$ ;

$A,B,C,D,E,F,G$ & $H$ are constants, $U,V,x$ and $y$ are function of time.

All initial conditions are zero. I have tried three options.

1. I have written the above in matrix form (Xdot = AX + BU), where X =[xdot x ydot y] and solved the system using Matlab, but the answer is not stable.
2. I have used 'dsolve' in Matlab, but its not returning a solution even after a day or so.
3. I cant use the Laplace transform method as the transform of U and V are unknown.

It would be of great help if someone can clarify.