I purchased a Goldstar one room air conditioner from Lowes and
installed it in my home office window. I built a little shelf on the
outside of the window to rest the back of the air conditioner on since
it's too deep to just sit on the window sill. The window it's in is
an old single pane sliding window which opens right to left like a
sliding glass door would. I've put a 3/4" piece of plywood over the
top of the a/c and it fits into the window frame nicely, however I am
woried about someone pushing the a/c or the board out of the window
and getting in the house that way. I have a wood dowel in the window
to keep it from opening any farther, but by removing the a/c you would
still have enough room to get in or to reach in and remove the rod.
What is the best way to secure this window?

Thanks,
Ed B.