Computer slow? Strange websites opening in your browser when you start it up? That's a good sign you've been infected. Installing Malwarebytes is a good first step to making your sick computer better.
https://www.malwarebytes.org/trial/
Click on the download button and save the installer to your computer.
To begin the installation, double-click on the Malwarebytes Anti-Malware installation file which you downloaded.
Malwarebytes will want you to confirm... a lot. Answer affirmative to all until it installs.
Once it is installed, it will offer to give you a 14 day trial of the premium features. If you uncheck it the program will need to be manually started to do a scan in the future.
Click on the Scan Now button and let it do its job.
When it's done have it remove what ever it finds. It may need to restart your computer to remove any infections it finds.
Once complete you will have a healthier computer.