Process Explorer (v11.20)
Windows task/process diagnostic tool
Developer: Winternals/Microsoft
OS: Windows
Price: Free
Site: http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx

A program has just stopped responding to input. Has it crashed or is it just busy thinking? Your system has suddenly slowed to a crawl for no apparent reason. What program is responsible? Traditionally, diagnostic tools like Windows' built-in Task Manager have offered answers to these sorts of questions. For those craving more detail than what Task Manager offers, there's Process Explorer.

Process Explorer is a bulked-up version of Task Manager aimed at more experienced users. Instead of the simple Applications and Process tabs of Task Manager, Process Explorer shows a large list of all the processes running on your system in a hierarchical list. Process Explorer's list is more comprehensive than Task Manager's — it splits out services from regular processes, for example.

Process Explorer has a variety of other useful features. Need to find a program hogging the CPU? Hover over spikes in Process Explorer's CPU graph, and it'll show the name of the process responsible. Wondering if a program's crashed or just busy? Turn on the CPU History display and you can track the processor usage of individual processes over time. Trying to delete a file from your system, but Windows tells you it's locked? Try Process Explorer's "Find Handle or DLL" feature and see if a process is using the file.

Process Explorer is far more useful than the standard Task Manager — so much so that Microsoft bought out the developer and began offering Process Explorer straight from the Microsoft site in 2006. Is there any higher praise?

Foxit Reader (v2.3)
PDF reader
Developer: Foxit Software
OS: Windows (versions for Linux, Windows Mobile and embedded Linux also offered)
Price: Free, $39.99 USD for Pro Pack
Site: http://www.foxitsoftware.com/pdf/rd_intro.php

Because PDF documents are now ubiquitous, so too are PDF readers. On Windows, Adobe Reader is the dominant application for viewing PDFs — no surprise, as Adobe created the PDF spec. But Adobe Acrobat Reader 7 was so overloaded with plug-ins and add-ons that even starting the program took a virtual eternity. Users with older, lower-spec systems also complained of performance problems when viewing large documents.

Though Adobe Reader 8 is much faster and more responsive, there's still plenty of room in the market for alternatives like Foxit Reader. Styled as a sleek, low-impact PDF reader, Foxit's advantages were more obvious when the bloated Acrobat Reader 7 ruled the land. But Foxit still feels slightly more responsive than Reader 8, and starts up slightly quicker as well. And then there's the matter of memory usage: to open the same 3MB PDF file, Foxit required a memory footprint of 15MB, versus Reader 8's whopping 100MB. (Your mileage may vary, of course.)

Other nifty features include tabbed document viewing, an interface improvement Adobe Reader would do well to pick up on. Unfortunately, some of Foxit's features are only unlocked with the $40 Pro Pack, like annotations (available in the free version, but watermarked). More glaring is the lack of a Firefox browser plugin, though one is offered for IE. But Foxit's performance improvements may be more than enough for heavy PDF users.

AutoHotKey (v1.0.47)
Macro/scripting tool
Developer: Chris Mallett
OS: Windows
Price: Free
Site: http://www.autohotkey.com/

For some computer users, the keyboard is king. These users know all the keyboard shortcuts to their favourite programs and cringe at the sight of other, less-experienced computer users who try and do everything with the mouse. It's for these hotkey-loving power users that AutoHotKey was created.

AutoHotKey allows you to automate repetitive actions in many different ways. One common use for the program is simple text replacement — prolific e-mail writers, for example, can type in a shorthand phrase like ":email:" and have AutoHotKey replace it with your e-mail address on the fly. AutoHotKey can also record a series of keyboard or mouse actions, and then replay them whenever you hit a specific hotkey—great for assigning hotkeys to often-used but hard-to-reach commands.

But AutoHotKey's scripting engine can go far beyond these basic tasks, opening up a wealth of possibilities to anyone with basic programming skills. AutoHotKey's many features include the ability to create forms and windows for user input, control mouse and keyboard movement arbitrarily, detect colours and match images to what's on the screen, run scripts triggered by various events like starting an application, and much more.

The downside to all this functionality is you need to be comfortable with writing your own scripts, meaning novice users will likely stick to the simple stuff or installing scripts made by others. But for anyone willing to dive into the API documentation, AutoHotKey is like a programmable swiss army knife for your computer.