On the shelf, software - otherwise known as "commercial software" - can be expensive, and incompatible, and outdated when compared to what's available online.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. Identifying Compressed Files Most files are compressed in .zip format (if you're using Windows) or .sit format (if you're using a Mac). The two most popular software programs used to compress and decompress files are Winzip and StuffIt respectively. There are other programs that do the same thing and there are even programs that can compress and decompress files for both the Windows and the Mac system. Banking is self-serviced through the desktop-clad ATM machine. Gas stations are self-serviced through a menu-clad touch screen kiosk. Most cash registers are Windows XP or Vista machines that send purchase details back to headquarters via the Internet (or a small Intranet). Having your weight, blood pressure, and heart rate measured and recorded is now a digitized process. Clicking an icon will open a tool or process a command that might also exist on a program's menu bar. Problems in this part of an interface are uncommon, however if you find yourself repeatedly clicking an icon with no results, you can correctly describe the problem by referring to the toolbar. Minimize, Restore, and Exit buttons - these three buttons are usually located on the right-most upper part of a program's interface and each allow you to minimize a program's screen, restore it to its original size, or shut down the program completely. Although those better-known brands may be a tad bit more expensive, the computer novice will appreciate the comfort in purchasing a computer from a business that has a long record of building quality products, and that has the funds available for fulfilling returns, trades, servicing, and warranties. Most computer users don't know which files are safe to delete and which aren't. The worst thing anyone could do is snoop around crucial Window directories and haphazardly delete files that don't look familiar. Doing so could render important programs inoperable, corrupt the Windows operating system, and possibly prevent the computer from even starting.