So costly that the temptation to pirate a little software here and there can be pretty tempting. Co-workers are familiar with this temptation and they're often the ones who "share" purchased software among those who need it. However the same temptation also prompts others to knowingly or unknowingly buy bootleg copies of commercial software or registered shareware. On one hand, it affords us quick and easy access to numerous conveniences such as bank statements, favorite shopping centers, school and health records, and more. On the other hand, it can also grant the same access to those who aren't supposed to get it. Although it's a rare occurrence, hacking has become the biggest criminal nuisance in computer history. But without seeing the extension, you wouldn't know it unless you double-clicked on it. The following list defines some of the most common extensions that you'll find on your computer. .au - This extension indicates a sound file. Most sound players will load up and play this kind of file. .art - This extension indicates an image file that was compressed with AOL (America Online) technology. But this method merely "relieves" the symptoms that these files induce - it doesn't attack the cause. These files need to be deleted - not "organized!" Of course, deleting files can be a scary adventure to most users. Most computer users don't know which files are safe to delete and which aren't. 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. You could even block instant messaging and email from anyone who isn't a fellow AOL user. Microsoft's help desk is good example. 3. Fan sites. Fan sites probably isn't a good name for this resource, but you can find websites that are dedicated toward supporting the users of a particular software program or piece of hardware. We've called them "fan sites" because the maintainers of these sites have no affiliation with the manufacturers that they support!