  Given a finite group $G$ and a faithful irreducible $FG$-module $V$ where $F$
has prime order, does $G$ have a regular orbit on $V$? This problem is
equivalent to determining which primitive permutation groups of affine type
have a base of size 2. In this paper, we classify the pairs $(G,V)$ for which
$G$ has a regular orbit on $V$ where $G$ is a covering group of a symmetric or
alternating group and $V$ is a faithful irreducible $FG$-module such that the
order of $F$ is prime and divides the order of $G$.
