There are a variety of reasons you may have arrived at Malware Removal and Prevention (MRP). If you are here to do a thorough system cleaning or just a checkup, then MRP will guide you through that process. Perhaps your computer is showing symptoms of infection: Popup ads, general sluggishness, or browser redirects, to a name a few. If that is the case, MRP will offer you a good chance at restoring your system to normalcy.
You may well have been instructed to complete Malware Removal before posting a HijackThis (HJT) log. HJT is a program which scans your system and allows you to create a log or report at the end of its analysis. The log created by the HJT lists many places on your computer that spyware and malware are known to target. The HJT staff are trained to interpret your HJT log and provide instructions which you can follow to repair your system.
Before posting your HijackThis log, we will have you run several malware removal programs and a system cleanup utility.HJT is an analysis and repair tool. It will not scan your entire system nor will it detect or delete all the files and registry entries associated with an infection. As such, it is extremely important to use the full system scanning tools we recommend before fixing anything with HJT. These automatic detection and removal programs address a broad spectrum of malware including adware, spyware, trojans, worms, viruses, and browser hijackers. We also advise you to run a system cleaning utility intended to improve your computer's overall performance and remove any infected files which may be hiding in your temporary folders.
This new preliminary scanning procedure will provide a dual benefit: Your computer will benefit from the thorough cleaning it provides. We in return, will benefit from being presented with a cleaner system profile containing only those infections which the automatic removal programs failed to eradicate.
It is possible that you may not even need to post a HijackThis log after completing the scans we suggest. If you are satisfied with your computer's performance, and feel your system is no longer infected, then you may decide to take that option. If that is the case, it is vitally important that you implement the safety suggestions presented in our Malware Prevention section to maintain your continued security. However, if you still feel that your system is infected or hijacked after completing the entire malware removal process, we invite you to post a log on the HijackThis forum.
Your compliance with this precleaning requirement, will allow the HijackThis staff to clean your infected machine much more efficiently. The resultant time savings will enable us to attend to a greater number of logs in a shorter period of time, thereby benefiting everyone involved.
Please follow all directions carefully. If at any point you need some sort of clarification, please, please, please ask us! As applicable, we have included links to the appropriate CastleCops forums. Finally, we would very much appreciate your feedback. Praise, suggestions, complaints, ... anything goes!
Source:
http://wiki.castlecops.com/Malware_Removal_and_Prevention:_Introduction