Note that many websites have their own advertising, unrelated to adware.
This toolbar is installed by active x download from their website. You must first check a box signaling that you have read their very long EULA. It will prompt you to install the file and before you know it you have toolbar on your IE browser.
From their EULA paragraph 3:
"THE TOOLBAR MAY BE OFFERED TO YOU BUNDLED WITH ANOTHER THIRD PARTY SOFTWARE APPLICATION (A "THIRD PARTY APPLICATION"). SUCH THIRD PARTY APPLICATION IS OWNED OR LICENSED BY A THIRD PARTY AND THIS EULA DOES NOT APPLY TO YOUR USE OF SUCH OTHER THIRD PARTY APPLICATION, REGARDLESS OF WHETHER THE TOOLBAR AND THE THIRD PARTY APPLICATION CAME BUNDLED TOGETHER. YOU AGREE THAT 2020SEARCH SHALL NOT BE RESPONSIBLE FOR ANY LOSSES, DAMAGES, INJURIES, CAUSES OF ACTION, CLAIMS, DEMANDS OR EXPENSES, INCLUDING LEGAL FEES AND EXPENSES, OF WHATEVER KIND OR NATURE ARISING OUT OF, RELATING TO OR RESULTING FROM THE THIRD PARTY APPLICATION."
Delete these files: