Internet popping up frequently

[A maid]

Since this evening I have random sites popping up with Internet Explorer and i use Firefox.
I haven't installed anything, went to a dangerous site or something.
Tried deleting my history and cookies and it still was there.
And just a while ago my virus scanner (AVG by the way) confirmed there were no infections.

Any clue or solution on this?

EDIT: AVG just said there's multiple viruses but can't delete it D: It's keeping it in quarantaine I guess, but will that help?

[Noah]

Yeah, it's a virus. Use the built in windows antivirus

[A maid]

I'll give it a go. Thanks