Several weeks ago, a program named BearShare suddenly appeared on my computer. I did not download it and have no idea where it came from! I uninstalled it thru Revo uninstaller and thought that I had gotten rid of all the registry entries, etc. However, now when I use the address bar to access a previously address website, BearShare comes up instead of the address that I wanted. I tried a System Restore to try to get rid of it but that did not work. I also ran a full scan with Malwarebytes but the problem remains. Any help will be appreciated. Thank you.

now when I use the address bar to access a previously address website, BearShare comes up instead of the address that I wanted

Please, explain the above part again.
What browser are we talking about?