Can I get a virus on Android 4.4.2 by clicking "no thanks" on one of those virus browser pop-ups? I opened a link using the built-in facebook browser yesterday, and pop-ups on the website kept asking me if I wanted to install some anti-virus and they had two options: No thanks and OK.  Normally I press the back button because I'm wary of clicking anything, but this time I clicked "Cancel."

I've noticed some weird behavior with my phone freezing this morning and now I'm paranoid.  Could have clicking "Cancel" actually installed something?  Was the message box option spoofed?
Well it's hard to know. Install avast anti-virus from google play and it will show any viruses (if there are any). But that 'Message Box' shouldn't have appeared, so that means either Facebook was hacked or you were using a fake Facebook app/page. Clicking 'No Thanks' on a webpage can't install anything unless you already have a virus on your Android. You should be safe if you were using the genuine Facebook app/page and that Settings&gt;Security&gt;Unknown Sources was unchecked.