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. .ttf - This extension indicates a font especially designed for use on a Windows system. Call them what you will, but their free help is immeasurable and without it, we wouldn't have some of the wonderful workarounds and unique problem solving techniques that we have today. 4. Usenet newsgroups. Another underused resource on the Internet, Usenet newsgroups have hundreds of discussion groups dedicated to some of the most popular computer systems, operating systems, hardware manufacturers, and individual software programs. Then let's say that the user of that computer downloads and installs Program B. Program B uses a file that Program A installed much earlier, but when Program B is run, errors popup. Those errors are the result of Program B attempting to use an outdated (shared) file that was installed by Program A. In order to fix that problem, the user would have to download an updated version of the shared file (which to say the least - is not an easy thing to find or do). This way, you can return to the beginning of a system and start over in case you get lost among the way. Another important choice that you want to keep your eye on is the choice to get help! This option may not be available on every device that you encounter, but when it is available, be sure to use it. There are many creative uses for home networking, however it's an ideal situation when upgrading each computer to the same capability is financially out of the question. On a home network, each computer has access to the equipment of the better machine in the group as if that equipment were their own. Traditionally, software is developed behind closed doors. A team of professional coders build it but the community at large isn't part of its conception. 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.