@Cruiser is right: run a third party anti malware program (Malwarebytes is the best free one I have ever used) to identify and eradicate any malware that has crept in.
However on my laptop I go further in two ways:
first, I also have AVG anti virus installed (it’s free also, except I did upgrade to AVG Internet Security Suite in order to gain a third party firewall). In a case where one program installs another without permission, there is a good chance you also picked up at least one virus as well, which is where AVG becomes essential.
Second: all legitimate software gives you the option of saving downloads to a specified file (Windows Downloads folder is easiest to use) and install later. I always click on “Save” instead of “Run.” This way, by hovering the cursor over the downloaded file and right clicking, you open up a floating menu of options. Clicking on “Scan with AVG” alerts you to the presence of any possible virus infections before you launch the installation process.
(Disclaimer: for a long time I didn’t pre-scan downloads for problems for a long time. However, back in October, I tried to install some free fonts downloaded from the website that appeared at the top of a Google search for Windows 8.1 free fonts. What I ended up with were: 6 unwanted programs, 9 viruses and 0 fonts. Lesson learned.)