I had a few browser hijacks recently. Oddly, they were from legitimate freeware programs downloaded from the official website. I clicked the "do not install" setting on the addons, but it still installed them. Maybe they weren't malicious, but they lost my trust when they appeared without my consent.
Basically I downloaded and updated the following: Avira Anti-virus, Comodo Internet Security, Microsoft Security Essentials, Spybot Search and Destroy, Malwarebytes and TDSSKiller (by Kapersky). A grand total of zero quid spent - It's all free software.
I went into safemode and then opened the browsers and disabled and deleted the addon, then independently ran the aforementioned software. I also processes from the MSConfig and deleted registry entries.
Like a moth to the flame nuke