I have not tried out the FreeFixer, and I will start out cautiously, because all depends on my judgement.

Basically freefixer is an upcoming tool which had quick updates and which is backed by experience of Mr.Roger (Author of Bazooka Spyware & adware Scanner and some other tools in anti-spyware scenario)

The updates are coming with some gap now, but, I am confident that it has bright future, as active development takes place further. Telling this as I had some decent amount of interaction with it's developer well from the initial stages of that project, it's a nice one with good future,

you can try it, while you can use hijackthis which is a proved one,