It manages the activity of every component and then displays that activity as a user-friendly interface (GUI). It keeps track of where things exist on a computer's hard drive as well. But perhaps most importantly for the end-user, the operating system is responsible for translating commands issued with a keyboard and mouse into binary code (010110101 stuff) that can communicate with a set of speakers, a printer, a scanner, and more. A computer user only needs to touch various boxes on a screen to control a computer. Sure, the programming behind such technology is extensive and advanced, but to the end user, it makes computer use less intimidating and plain easy. Of course when we talk about operating a computer, we envision more involvement than speaking on the phone or touching things on a screen. Some viruses are a combination of each, however they can be further identified according to where they're located on a computer. A virus originating from the boot sector of a computer is a boot-sector virus and this nasty devil does its dirty work the moment a computer is turned on. A virus that attaches itself to (infects) other programs is a file virus and activates the moment that an infected program starts. mid - This extension indicates a sound file created with a Musical Instrument Digital Interface. 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. The problem is that an uninstall program doesn't delete the orphan files it leaves behind because they were never part of the program when it was first installed. An uninstall program can remove only the files it placed onto a hard drive during its install routine. So while Windows' Add/Remove Programs can remove an entire program, you'll need to get rid of those pesky little things with a more advance file cleaner like CleanSweep for example. Cheap and Fast Software An Introduction to Shareware Visit any computer store today and you'll find what seems like miles and miles of software on sale. Certainly enticing buys, there are a few problems with buying software off the shelves. On the shelf, software - otherwise known as "commercial software" - can be expensive, and incompatible, and outdated when compared to what's available online.