Thank you for your interest. You should download the Tor Browser Bundle. You 
can extract it to a directory of your choice in your user directory. It comes
with a Firefox-based browser configured for Tor. You can then use that new
browser for anonymous surfing, alongside your regular browser for normal
browsing. Tor does not "anonymize" other applications on your system by
default, and you should not try to do so if you're not technically skilled.

As such, it will leave all your existing settings in place and not change 
anything. If you don't like it, you can simply delete the Tor Browser directory
and it's gone.