Help! My computer has a mind of its own

:confusedMy computer is running super slow. I keep getting popups and the browser page will redirect on its own and other browser pages will open bythemselfs. I get pop ups about my pc being infected and I do not know what to do. A friend of mine told me about this site and I wondering if anyone can help me?

 

Hi steveanders!
Welcome to Major Geeks!
Your title looks so familiar.
Please work through the instructions in the READ & RUN ME FIRST
As you work, you will most likely begin to find some relief to this problem. Please note that there are different instructions for different operating systems at times. Note the ones that apply to your operating system. If you can't do something, please try to go on with the next thing. Attach the requested logs with your next post.
abri