TeamViewer is an excellent screen-sharing and file-transfer app that can be used to facilitate business collaborations, remotely access a second computer, or help distraught relatives diagnose and cure computer problems. Along with being free for noncorporate use, it gives users precisely the tools they need to share screens securely, send files with a minimum of hassle, control access rights, and even flip which user has control. The options available while you're in control work smoothly. You can maximize the pane that the other computer's screen is visible in, as well as utilize several smart options from a drop-down toolbar in the center of the window. A big X lets you close the connection, while the Actions button lets you switch whose in control, disable remote input, and reboot remotely. The View menu hides options to adjust the screen resolution, the optimization toward speed or quality, and control multiple-m...