Don't open files without scanning them with an anti-virus/anti-spyware program. In the past, the warning was to avoid opening files from people that you don't know. Today it's really not safe to open files from anyone (without scanning the files) because that's how viruses get spread - through files - even by mistake. It's costly to produce and as you can probably guess, that cost is passed on to the end user: the consumer. Open source software on the other hand is free. Free to download, free to install, free to use, free to modify, and free to share. Started over twenty years ago, it's a phenomenon that is gaining in both popularity and exposure. 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. As tempting as it is, it's still illegal and the punishments/fines for sharing commercial or registered software is too much for one to bear. "1 In the past, we would be comfortable in telling new computer users not to worry about viruses and that catching a computer virus is rare. Today, that would be some of the worst advice we could give anyone. As reported in countless news reports, computer viruses are rampant and they're extremely worrisome. Windows Media Player will open and run these files, however they don't sound like normal .wav or .mp3 files (described later). .Mid files are designed to product synthetic sounds using a computer's sound card. .mp3 - This extension indicates a sound file that authentically reproduces voice and/or music. Sometimes, the representatives of these companies participate, but most of the time, the support in this group is user to user, which is just as valid because you're working with a team of experienced people. 5. Support Lines. Another source for help that we shouldn't forget are the support systems of various manufacturers.