If you've been typing $^$ into the regular OpenOffice Writer search and replace dialog and coming up empty, try this plugin. It's awesome. It lets you look for a series of empty paragraph returns, or a carriage return at the end of a paragraph plus one empty return, and MUCH much more.
Download then choose Tools > Extension Manager to install. Restart OOo and you'll see a new icon in the upper left corner on the main toolbar.
Here's the page.
Here's the icon you get when you restart OpenOffice.
Here's the window.
And here's an example of what the shown expression found.