On the shelf, software - otherwise known as "commercial software" - can be expensive, and incompatible, and outdated when compared to what's available online. Fortunately, there's an alternative to commercial software and although it isn't new, it's one of the most under-exploited opportunities in the computer industry. You and your children may not always agree about what's appropriate, but as a guardian, you're in control and you're ultimately responsible for their safety. Take the time to investigate software tools that put you in control and allow you to block access to certain websites. If you use an online service like AOL (America Online), you can use its internal Parental Control settings to block access to various chatrooms and websites. Today's "older" computers are perfectly capable of accommodating the needs of young PC users, and they're excellent machines for playing educational CDs, small multimedia files, or games downloaded from the Internet. And don't forget the most important role they play in a child's homework-clad life: A simple encyclopedia CD on a used computer makes excellent research tool (not to mention a rather fancy calculator! Both Internet Explorer and the AOL service software can display this kind of file, however if you don't have AOL installed on your system, Internet Explorer will display it. .avi - This extension indicates a video file playable by most multimedia viewers including Microsoft's Media Player. .bmp - This extension indicates another image file that might have originated from Windows Paint program. " "Scan Your Disk for Errors!" Although these two activities are important, there's more you can do to extend the life of your computer beyond today's predicted two-year span. In fact, by following the simple advice below, you can enjoy the use of your computer to up to five years or more - reserving expenses to simple software upgrades rather then complete and costly hardware upgrades. In these situations, problems occur the moment that a piece of software attempts to access the things (hardware, memory, space, resolution, etc.) that it cannot find. Because some programs share common files, errors can also occur when these shared files are not up to date. For instance, let's say that Program A is already installed on a computer and it's working just fine.