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. It stands for "True Type Font." .txt - This extension indicates a plain text file that can be opened with Notepad. .wav - This extension indicates a sound file that like the . Basically, computer errors are the result of a number of things that may or may not have anything to do with the way the computer is used. They "operate" whenever there's a conflict among commands. Remember that computers essentially run off of a series of commands and it's usually a smooth process. Dust Kills Cleaning the Unit Fan is Essential Computer Care Between taking care of the household, the kids, the pets, and the district PTA, computer care is probably one of the last things that you think of doing on a regular basis. Without a regular maintenance schedule however, you could find out (the hard way) that a neglected computer is an energy hog - one that works harder than it needs to and one that could be a financial burden to replace. The data that a program receives is called input and data that the program generates is called output. Other times, the data is unknown. If the program were working with a simple algebra equation like, "x + 5 = y," the variables "x" and "y" would be unknown pieces of data. exe extension, take note that although the file is compressed, it's typically a file that will install a program onto a computer. .Zip or .Sit files don't install software - they merely archive a collection of them into one, or they significantly reduce the size of a larger one. Decompressing Files Assuming that you have Winzip or StuffIt installed on your computer, you can access the files archived inside a . 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.