Windows 3.x features graphical user interface, multi-tasking program execution, virtual memory, and so on.
Graphical User Interface is an easy-to-use user interface. Its general meaning is that most programs use windows common graphical controls (such as buttons, edit boxes and so on) to interact with the user. This makes the user feel easier to use programs, and in this way many common tasks can be done with only mouse clicks. Since to most computer users using a mouse is easier than using a keyboard, Windows means a great advance to them.
Multi-tasking Program Execution means that on one computer several programs can be run simultaneously. On the other hand, the user can share information among the running programs and he can also do many things at the same time. For example, the user can listen to music while he is writing a document. Another example is the user shares information between the Notepad and the Calculator in order to do a calculation and writes its answer into the document. This job can be done by using the Windows Clipboard. The advantage of multi-tasking can also be seen in this case: when your computer is idle or not very busy, Norton Speed Disk optimizes your drives in the background. Thus you don't need to start it and wait for it to complete. Windows 3.x, like traditional Mac OSes, use collaborative multi-tasking. That means that every program should actively release the CPU, or the system will hang.
Virtual Memory is such a concept: when the system runs out of memory, the operating system swaps unused data in the RAM onto the disk. This feature lets you run more programs than the amount the RAM can hold. This means, old computers with little RAM can also run large or many programs. Of course, the use of disk instead of RAM slows down the computer, so this feature should be used only when the task is not time-critical.
Windows 3.x supports file association. This lets you open a file by double-clicking it in the File Manager. The file association information is stored in the Windows Registry. In newer versions of Windows (such as Windows 95, etc.), the Registry contains more information than File Association, such as uninstallation information, component/program registration information.
Other features of Windows 3.x include: no 640KB conventional memory barrier, True-Type fonts (3.1 or higher) and so on. One great problem to MS-DOS users are the 640KB conventional memory barrier. This forces the user to consider what programs should run and what shouldn't run. In order to balance TSRs and normal programs in order to fit all of them into the memory, the user may need too much knowledge, too much help and too much time. In Windows 3.x, this is less the problem, because free memory over 640KB can be utilized by programs more easily. In future versions of Windows, this is less and less a problem that in Windows 98 and higher this is almost not a problem.
True-Type fonts let the user enjoy WYSIWYG (what you see is what you get), because they look the same both on the computer screen and on the printed paper. What's more, they are fully scalable. It is really a good feature.