An annoying trouble in Windows 8.1

I'm a newbie of Windows 8.1. Now I doubt that the new system has been infected by malware that causes many popups marked as "by daugava". I found many tutorials like this one on google just introduced how to clean off pop-ups from Windows 7. So do you guys know how to remove popups and malware from Windows 8.1? Thanks.

Here's another step-by-step to remove Daugava manually from Win 7 thru Win 10 (I wouldn't install any software, I would follow the manual method) -> How to remove Daugava (ads, pop-ups, banners)

As suggested I would then run a malware tool as well to ensure you didn't also install something more than nasty browser addons.

I would be very careful about where I go with my machine and what I install should you be able to clean this up fully.

You have to use some third party malware remover software or some antivirus to do that, in my opinion malware bytes is the best malware remover software out in the market, it is available online for little charges, it is available for bath mac and windows os.