The Webroot Removal Tool is a simple program that will uninstall and remove all traces of Webroot security software from your PC.
Of course in theory the "uninstall" program should do that, but removing antivirus software isn't always so straightforward. It has to dig deep into your system to protect it, making Registry changes, setting up services and more, and occasionally you'll find the uninstall option doesn't do a sufficiently thorough job.
If you're trying to run some other security tool, then, and it's complaining that you've a Webroot package installed - even though you thought you'd removed it some time ago - then you need to download the Webroot Removal Tool. There's no installation required, no options to set, just run the program and it'll search for and remove any leftover traces of Webroot packages. The program even deletes itself - that's what we call thorough.
Please note, the Removal Tool may not work with beta versions of Webroot products. If you're having problems uninstalling a Webroot beta then consult their support pages for more advice.