A diagonal matrix with all eigenvalues equal to zero is the zero matrix, which has no linearly independent vectors. If at least one eigenvalue is zero, it implies that the matrix cannot have a full set of linearly independent eigenvectors. The zero matrix has only one eigenvalue, which is zero, and does not provide any linearly independent eigenvectors. The discussion clarifies that the original question was misphrased, focusing instead on the implications of having zero eigenvalues. Understanding these properties is crucial in linear algebra.