If persistent spyware is bogging down your computer, you might need HijackThis. The tiny program examines vulnerable or suspect parts of your system, such as browser helper objects and certain types of Registry keys. Pressing the Scan button generates a log of dozens of items, most of which are just customizations. Don’t check off an item and hit the Fix checked button unless you’re sure it’s malware. Clicking Info on selected item tells you why the entry was flagged as suspicious, but not whether it’s actually malware. To find that out, search the Web for that item’s name or go straight to a forum, such as SpywareInfo or Computer Cops. Saving the log creates a text document you can post to these forums.

The latest version adds powerful tools to the Config window. The process manager and hosts file editor help you excise virulent infections. The unique ADS Spy tool scans for alternate data streams, which some browser hijackers use to hide from spyware removers. The program still installs into whatever directory in which you unzip the file, which can make it hard to locate. HijackThis is a serious tool for any user who needs to root out a serious infestation, but wield it with caution.

HijackThis is a great malware removal tool, but it’s not for the average user. The list it generates is full of innocent or harmless entries and items that should be there. Its main intent is to show you what’s what, not make a determination of what’s actually a threat–so utilizing it effectively requires a fair amount of knowledge. You can select items on the list and have the program delete them, so if you don’t know what you’re doing, you can create quite a mess despite the automatic backup function that allows you to restore items you’ve removed. HijackThis’s other features include a handy process viewer and an ignore list that you can place items you’ve deemed as innocent to so they’re not scanned in the future.

Even if you don’t use HijackThis to actually remove threatening items, it’s handy for learning about what they are and can be used for. Simply select an entry on the list and click on the “Info on selected Item…” button for information on what the item is and an example of how it might be used malevolently. Just stay away from the “Fix checked” button until you’re confident that you know what you’re about to zap.