Most of Windows 7's accessibility options are, at best, of dubious usefulness to the average PC user. And that's fine, as they're generally designed for people with special needs, and can be easily deactivated. There's one accessibility option, however, that can be a big help to anyone: Mouse Keys.
If the name didn't tip you off, Mouse Keys is an accessibility option that allows you to control the mouse cursor using your keyboard. This can be useful in two ways. First, there's an obvious utility to Mouse Keys if your mouse ever breaks, or if you have to disconnect it for any reason. Second, Mouse Keys is very precise—a single press of a key moves the cursor by one pixel, making it useful for any application that requires ultra-high precision, like Photoshop.
1. Enable Keyboard-Driven Mousing
First, open the Ease of Access Center panel from inside the control panel, then click the option marked "Make the mouse easier to use" (below).
You'll see a checkbox labeled "Turn on Mouse Keys," and beneath it a link to "Set up Mouse Keys." Click the setup link, where you'll find all the options for using Mouse Keys (below). By default, the Mouse Keys hotkey is enabled, which is Alt + left Shift + Num Lock. Unless that happens to be your favorite keybind for WoW, just leave that enabled for quick access to Mouse Keys. There are two sensitivity settings—we recommend you max both of these out, because even then the Mouse Keys cursor moves painfully slow. To help that, we also recommend you check the box that makes the mouse move faster while the Control key is held down. With this setting, it's easy to get your cursor wherever you want it in a hurry.
2. Control the Mouse
Once you apply your setting and click OK, you should be able to move your mouse around with the number keys and CTRL. You'll probably be confused at first as to how to click. It's a little complicated, but here's the breakdown:
To left click, press the 5 key.
To double-click, press the plus key.
To switch to right-click, press the minus key. Now 5 will right-click and plus will double right-click.
To switch to simultaneous right- and left-click, press asterisk. This works the same way as the above.
Finally, to switch back to left-clicking, press the slash key.