AYG - it's easy to get confused between the Operating System - eg Windows 8 - and the internet browsing program - which might be internet explorer, chrome, firefox etc.
I think you mean the internet browsing program has caused problems?
So, here's whaht to do.
First, check your computer for nasties. Your anti-virus program should be doing this, but if it's missed something, download the free malwarebytes and give it a go.
Use this link, make sure to choose the free download, and follow the instructions given.
You might find this then sorts the issue.
However, if you're being bothered with popups and adverts you need to run an adblocker program. These are accessed in different ways according to which browser you're using. I use chrome all the time with adblocker enabled, and never see an advert that I don't want.
Let us know how you go on!