Avoid PUP how?

[virtualuser]

PUP (potentially unwanted programs) usually comes with free software (e.g. toolbars, search engines). I recently found a trovi browser hijack on a friend's computer that's hard to remove. I ended up using adwcleaner to get rid of it.

In addition to being careful to uncheck "bonus software" when installing free software, what is a good second line of defense against accidental installation of PUPs? Anti-virus software may not raise any warning because they are technically not virus. adwcleaner I think only scans installed programs, but does not actively prevent PUP from installing.

[Dun]

Malwarebytes Anti-Malware real time protection.
Unchecky http://forums.mydigitallife.info/thread ... g-software
http://www.youtube.com/results?search_q ... cky+rewiev