Batch files are small text-based documents that contain a bunch of these commands on their own lines. When executed, they would process each command without the user having to type each and every one of them. When Windows was developed, the need for typing commands was essentially eradicated thanks to the introduction of the point-and-click (mouse) interface. Sure, computer stores do their best to keep their inventory up to date, but when you can download version 5.6042 of a shareware program as opposed to buying a commercial 3.0 version from the local computer shop, there's just no comparison. Which brings up our next point. Just where does one get shareware? mp3 - This extension indicates a sound file that authentically reproduces voice and/or music. Windows Media Player will open and run this kind of file. .scr - This extension indicates a screen saver file. .sit - This extension indicates a Macintosh archive StuffIt file. They will not open on a Windows system without a special utility. Sometimes the links are harmless and attempt to con the reader into volunteering personal information (credit card number), but other times the links attempt to download harmful software onto a computer. Your best protection against computer crimes is your own knowledge. Hopefully the suggestions above will prompt you into taking appropriate action and into protecting your computer with the suggested tools. Instead of speaking to a human being, chances are that you spoke to a computer that not only responded to what you said and followed the commands that you gave it, it also asked you for more information such as your full name or credit card number. In this case, a person (such as yourself) operated a computer without even knowing it! But sometimes Windows' Add/Remove Programs isn't enough. Although this software does a pretty good job of removing unwanted programs, it can leave some files behind even after a complete uninstall - files which become orphan files. And it's these orphan files that can really clutter up a hard drive and shorten the life of an otherwise, young and robust PC.