A computer is basically pretty stupid. It can only do what it is told to do. It just does it pretty fast.
As time goes on, computers get faster and do more things. The basic elements of the computer are the CPU (central processing unit) sometimes called the tower, because for the last few years, the majority of the computers are in a free standing floor mount case.
The first personal computer systems were usually in a small case which sat on the desktop. Hence the term desktop computer. Today, any computer which is not a laptop, notebook, or any other fancy name they come up with as time goes on is considered a desktop.
The next element is the keyboard, which is used to do the typing. A mouse follows giving the capability to move a cursor on the screen to point to items to be selected.
And finally, the screen, or monitor which visually displays the programs and data.
The main differences occurring to computers as time goes on is the processor gets faster, the hard drives get bigger, you get better sound and video cards, and on and on.
Everything the computer does has to be run by a program, usually referred to as the software, which gives you the capability to do everything from running Windows, doing word processing, working with graphics and audio files, browsing the Internet, doing email, etc. Yes, even Windows is a program.
The computer has to start the Windows program when you turn it on. All the programs, your data files, virtually everything is stored on the hard drive. For simplicity of understanding, just think of the hard drive as a circular magnetic disk which stores data in a magnetic form (+ and -) and it knows how to read the data in this format. The data is usually stored from the center toward the outer edges, and there may be several disks, or platters in the hard drive. Lately they have developed sollid-state drives (SSD's) and as time goes on, I'm sure there will be more developments in the storage arena.
Things are written, or stored, to the disk as they are loaded, so, a program or file can be physically anywhere on any of the platters. Files are stored on the hard drive in the order you install them.
The computer keeps a record of where everything is, kind of like a road map, so when you start up a program, the computer goes out and finds the program and configuration files, loads them into memory and starts up. It then goes out and finds any data files you are using when you open them up.
In the old DOS days, you could only run one program at a time. Let's say you were working on a spreadsheet and you needed to compose a letter with references to the spreadsheet. Unless your memory was really great, you had to either print out the spreadsheet or make notes because you had to close out the spreadsheet program, then start the word processor. You then had to create the word processing document and save it.
With the advent of Windows, the need to stop one program in order to run another was eliminated. Although the early versions of Windows left a lot to be desired, today the operating system has evolved into a more workable format. We still don't run programs simultaneously, but rather we swap from one program to another. Although the computer seems slow when it is starting up and shutting down, it is really doing a lot of things very fast.
Every program you put on the computer writes data to the Windows registry which has all the information on the hardware in the computer, program information, fonts, etc. The registry files are literally thousands of line of code which is the heart of the Windows system. Windows has to make sure to check every font, driver, etc. is available and working in order to make sure things will work OK. I don't want to get technical so we will leave a lot out of these discussions and only put in what you really need to know.
When you start a program, the computer has to go to the hard drive, find the program and configuration files and load them into memory. If you start a second program, the computer has to take a snapshot of what is already loaded in memory, save that information to the hard drive, go out and find the files to start the second program, then load them in memory. If you now have two programs running and you want to go back to the first program the computer has to repeat the process of saving the active program information to the hard drive then it looks up the info on the program you want, reloads everything back into memory and now you can take up where you left off. So with Windows, we aren't multitasking, we're task swapping.
The biggest advantage of the Windows operating system is being able to move, copy, or link data from one program to another. Now you can take that spreadsheet and link the pertinent data directly to the word processing document and let the computer do the work. You can even link data, so when it changes in one program, it will update in the other one.
One of the most annoying problems for a new user is the myriad of ways to do things. In their attempt to keep everyone happy, Microsoft and the software companies have attempted to give you several ways to do everything but have also created a lot of confusion. Try not to be intimidated and if you are feeling overwhelmed, just take a break and come back to the computer later.
The one thing I would like you to understand, since everything is on the hard drive, is that keeping the hard drive cleaned up and healthy is very important. The three most important things you need to do are:
Backup your data
Think of the hard drive as a filing cabinet. It has to store every program and every piece of data you save. It has to be able to find those things quickly and use them. Hard drive failure happens and if it happens to you, everything is gone, so you need to keep everything backed up. This is the most difficult thing for anyone who is new to computers. Programs and data are stored in many different places and you need to make sure it is all getting backed up. Sometimes it pays to have someone come in and setup the backup for you. You can back up the whole hard drive but this has drawbacks. You need media large enough to do it and sometimes even though you have the backup, restoring the data can be difficult. Today, storage has become more affordable, so, I recommend using disk imaging software to backup everything on your computer 9this is particularly important if you have an SSD drive which can lose data if the circumstances are right). See this discussion for drive imaging software.
I recommend backing all your data, email, address book, configuration files, custom dictionaries, and for people who use Microsoft Word and have done any macros, Autotext entries, or button bar customization, you need to back up the normal.dot file in Microsoft Word.
If you aren't using disk imaging, one thing which helps dramatically is if you have an understanding of how the hard drive works, you need to store all your data files in directories which are being backed up. If you add folders under folders which are being backed up, they will automatically be included in your backups. Also see backups. Since backing up can get rather involved, you should have a consultant go over it with you so that you can get it right, before something happens. There are endless folders where data is stored for all the programs you use, so again, get a disk imaging utility, they are inexpensive compared to losing your data.
The antivirus programs now usually do a good job of updating themselves automatically, so the issue of updates is not as difficult as it used to be.
There are utilities built into Windows which will keep your hard drive checked and healthy. Defragmenting the hard drive is an important issue, click here for more information, again, if you have an SSD drive in your system, don't optimize it, that will cause excessive writes to the disk and it doesn't require optimization.