Did you just find an add-on in Mozilla Firefox called Power-SW 0.96? If you don’t know where it came from, it was probably bundled with another software download. I found Power-SW in an unofficial Google Chrome download, that was digitally signed by Advertiso GmbH.

If you’d like to remove Power-SW, you can easily so by checking it for removal in FreeFixer.

Any idea how you got Power-SW on your machine?

Update: The Firefox team knows about Power-SW and shows it in the “Add-ons may be causing problems” dialog. Good job!