HiJackFree

Program: HiJackFree

Website: http://www.hijackfree.com/en/

License: Freeware (For private use)

Description: A-squared HiJackFree is a detailed system analysis tool which helps advanced users to detect and remove all types of hijackers, spyware, adware, trojans, and worms.

Note: I've seen in a couple places that this "just works" portably but not sure about registry or other bits that may be left behind.