A FREE solution is to go to
www.Downloads.com and look for Panicware's Pop-Up-Stopper Free
Edition.. It is a small download and seems
to block lots of pop-ups, unders and arounds
that try to get by the browser privacy
settings. You can enable, disable from the
task bar and has an uninstall. Has other
options and Worked with Mozilla. Worked well
for me. No more annoying pop unders !
SteveRF