"Are there other free content filters similar to K9?"
I have used K9 Web Protection on the computers in our classroom but when I tried to install it on a separate laptop I see that K9 has been purchased by Symantec and of course Symantec wants me to start using their paid product. I only need a basic content filter for this laptop which will access the internet via a hotspot so there is no way to filter content with the router. I am looking for a software solution similar to K9 which runs in the background and ideally has settings allowing me to set filter levels. Although K9 was free, I am willing to pay for such a product, but I don't need "Norton Antivirus Plus (regularly $59.99) to K9 subscribers for only $39.99". Furthermore, last time I used Norton it slowed my system down to a crawl and this laptop is already an old clunker, limping along with Windows 7 and 4GB of RAM. I definitely don't need Norton slowing it down every further.