IE is an Internet browzer written and owned by Microsoft. Firefox is an Internet browser written by the Mozilla Foundation and released as
open source code. Anybody can download, modify and compile the code. It is free. There is lots of free open source software out there. The quality, security and reliability is every bit as good as proprietary software.
You can download Firefox here: http://www.mozilla.org/en-US/firefox/fx/.
After you download and install it, start it up and got to the "Tools-Addons" menu and search for and install Adblock Plus.