message " this program has performed an illegal act."

[Jacqueline Folwell]

Many times when in my e-mail or other programs both my
husband and I get this message on the screens of both our
comps. " This program has performed an illegal act and
must shut down" and it does shut the programs down. All
we are doing is checking our e-mail or playing games or
into photo express or other simple programs. Why do we
get this message and how do we get it to stop showing up.
It also removes most of the icons in the desktop bar at
the bottom right-hand side. Hope someone out there can
help. Thank you so much.