Simple Upgrades, Complex HelpersMake your mouse mighty, tweak Windows massively, and crush cosmic creepy-crawlies.

Sometimes a simple fix can do the job, and sometimes you need the works. This month we look at an easy-as-pie mouse utility, a feature-rich tweaking program, and an arcade-style game that builds in complexity.

Teach Your Mouse New Tricks
Your mouse's scroll wheel can be handy, but it's a one-trick animal. KatMouse adds new functionality to the wheel, making navigating multiple windows easier and faster. The freebie lets you scroll through windows without selecting them first.

KatMouse leaves your keyboard to focus on a given window while allowing your mouse to scroll other open windows. If you IM or e-mail with a browser window open, it's balm to your aching hands.

Another nifty feature sends a window to the bottom of the heap: Click the scroll wheel, and KatMouse banishes the window on which your pointer rests to the back of the queue. When you have a big window blocking others, this action takes less time than clicking around or using the taskbar to bring up other programs.

Though KatMouse doesn't promise to work with every program, I found that it worked with the current versions of Firefox and Internet Explorer. Developer Eduard Hiti offers KatMouse for free, but accepts donations for his efforts. Free/donationware.

Go Nuts for Pitaschio
Most PCs could stand some usability upgrades--but who wants to spend hours, or a fortune, getting them? With Pitaschio (yes, that's spelled correctly), making dozens of Windows tweaks is as simple as checking boxes--and it's free.

Pitaschio's very first window presents dozens of check boxes you can use to tweak the taskbar, disable sometimes-troublesome keys (such as Caps Lock and Insert) or the maximize and minimize buttons on windows, and more. The Autoraise function pulls to the top any window you mouse over.

Mouse shortcuts deliver extra power, activating different functions depending on where you click (desktop, taskbar, title bar). You can customize each mouse or mouse-and-key combo by assigning options such as turning off the monitor, opening Control Panel, and changing virtual desktops.

Japanese developer Ara hands out Pitaschio at no charge--yum. Free.

Don't Let 'em Bug You
Stopping an insect infestation is a blast--no, make that a loud implosion. In the seemingly simple arcade-style game Cosmic Bugs, armored insects have invaded your space station and stripped it to the girders. Your mission: Repair the station and crush the bugs.

掌握基础知识是很容易的。你身处e under no time limits, and you rarely target bugs directly. Instead, you shoot lines that seal off sections of the station. If you trap bugs inside, the bugs get smooshed--but if the lines don't completely extend before a bug reaches them, your lines become insect chow.

As you sanitize the station, the levels grow more complicated. Some insects crawl along the girders, and other sail through open spaces; each moves at its own rate and in a distinct style, so sealing them all up is a challenge. Various power-ups give you an edge if used wisely. But be warned: The bugs get power-ups, too.

Cosmic Bugs can start your heart pumping, but the lack of time limits lets you proceed at your own pace. I defeated a satisfying 25 levels by the time the hour-long demo expired. Twenty-five down, only 500-odd more to go after paying for the full game. Free 1-hour demo, $20 for full game.

Did you have an interesting experience with one of these programs? Is your favorite file missing from PC World's Downloads library? E-mail your comments toLaura Blackwell. Messages containing attached files will be deleted unread.