i have been using firefox and youtube downloader and tried to download a bill hicks video from a website i wasnt familiar with, when i saved the file and tried to open it, it just asked to install a few different toolbar apps, i refused and just decided to try and delete what the download and cancel. im pretty sure i cleared all traces of the file but when i open the internet browser the browser goes black and im below the search bar it gives me the option to fix the "problem" but i have to register and pay. whenever i load a site it works fine, but if i search something and it comes up with all the websites i can choose from, the browser goes black again. any ideas or info? i also have cc cleaner, but what other free programs could i download to keep my computer save and running well? thanks!

so i should just get rid of mozilla firefox completely? and i think i had avast but my trial ran out??