Ever had an advert appear on your screen while browsing that you weren’t expecting? Chances are it’s adware.
These programs tend to insinuate themselves by grabbing a free ride on the back of software you download from within a browser. Those free downloads that look so enticing are the usual culprits. For example, I’ve downloaded a couple of free video downloaders, only to end up with PUPs (potentially unwanted programs). Those video downloaders work fine, but they were free because of their hidden payload.
Some anti-virus programs will detect them on a deep scan, but a faster way is to use a selective program like the freeĀ AdwCleaner (now owned by Malwarebytes).

It is very easy to use. Just press Scan Now and off it goes. When it’s finished, it presents you with a results screen:

Click Clean & Repair. You are prompted to save any work that’s open:

If you click Click and Restart Now, the system will close down, hence the warning.
When the system reboots, you see this:

As you can see, only two of the three threats were removed. Clicking View Log File revealed:

The one it didn’t delete is WOT (World of Trust), which is correct. Though it has the profile of a PUP, it’s a worthwhile security feature.