  We establish effective versions of Oppenheim's conjecture for generic
inhomogeneous quadratic forms. We prove such results for fixed quadratic forms
and generic shifts. Our results complement our companion paper where we
considered generic forms and fixed shifts. In this paper, we use ergodic
theorems and in particular we establish a strong spectral gap with effective
bounds for some representations of orthogonal groups which do not possess
Kazhdan's property (T).
