I had an issue on my machine one time and went to a site suggesting hijackthis and superantispyware and others I'd never heard of until then. Went through the instructions on a post and it did seem to fix my problem partially, (after having installed and run about 7 different programs). So in the end I just gave up and did a clean install. After having restored everything on my system partition half the files I had downloaded from the so called "forum" turned out to be infected themselves.
All in all I don't trust such software, and so called internet "experts" who purport to guide you through the result log files are to be treated with extreme suspicion.
These days, I never trust any software available for download on forums etc. I'll always look for a manufacturers website and use software recommended by reputable sources (such as pc magazines, microsoft etc).
At the end of the day there is no substitute for backing up your data on a regular basis in a separate location, (different logical partition at the least), having an image of a clean install with all your apps and running a decent anti-virus program. Messing around trying to "save" a heavily corrupt and infected system is pointless and a complete waste of time. With the amount of storage you get on modern computers there is just no excuse for not partitioning it to segregate user data from system data. Such a set up will get you out of 99% of "worst case" infections using a quick wipe and clean install/re-image, without any loss of precious data.