This may be worth a read for some users. Really sneaky and just goes to show the constant battle users have to keep 'bad' browser extensions off their machine.
Note the new Google Software Removal and Browser Reset Tool mentioned near the end.
Being careful with addons/extensions is a must! The comments about CNET's download site in the article were interesting, but already known as an untrustworthy site to download anything from. The only thing CNET has I'll bother with are their car reviews on YouTube.
My mother installed some cleaning tool on her Kindle Fire (no it wasn't CCleaner) that was recommended by an Amazon.com tech support person to "make it go faster." Long story short she ran it only once, and it nuked the Kindle making it unable to start anymore. I had never heard of that cleaning tool or company behind it and told her to remove it, but she didn't listen to me.