Has your computer slowed down? Does it take forever for a file to 
open. Do you think your computer is about to crash? Take heart 
it probably just needs a little soft maintenance. What is soft 
maintenance? Think about your vehicle for a moment. Hasn't it 
gotten sluggish? Won't accelerate like it used to? Is using more 
fuel than normal? I am not sure I have even met anyone who has 
not experienced this. What is the most common cure for the 
vehicle? A tune-up right? The same goes for the computer.

Hardware failures are usually pretty obvious.  There is an odd 
noise, a total system break down, blank screen and or error 
messages.  Getting slow is usually for reasons other than 
hardware.  And most can be remedied by using the software that 
came with the machine.  Some computer systems come with operating 
system that are more self adjusting than others.  The Linux 
small computer OS is based on UNIX the operating system of the 
internet.  This is a very self-sufficient, self-maintaining OS. 
It quite automatically checks for broken files and refreshes them 
from master copies it keeps in a protected place on the hard 
drive.  The Apple Macintosh OS is also UNIX based and pretty much 
trouble free.  Every time the system is turned on all software is 
verified and corrected as needed.

The most popular operating system in the world is Microsoft's 
Windows in all its incarnations.  From Windows 95 to XP there are 
processes that need to be invoked manually.  Unlike UNIX based 
OS's only a select few files are readily available for automatic 
correction.  The others exist only on the original installation 
disk.  Special modes of operation provided for the reconstitution 
of the operating system.  This is the hard stuff. The kind of 
thing you would need a technician for unless you are very 
familiar with Windows.

The computer hardware is just electronic devices.  Without 
software it is just so much Silicon, electric motors and 
connectors.  The software is the instructions that tell the 
hardware what to do.  At the lowest level is the DOS, disk 
operating system.  This software takes care of the 
"housekeeping".  It controls the CPU math functions, disk 
accessing that is to say the physical movement necessary to put 
the play head in the right position to read the data magnetically 
from the disk. It manages the use of memory and access to or 
interface with peripheral devices like modems, sound cards, 
high-speed access connect ports, etc. All of this is far removed 
from what you see on the screen and occurs with no interaction 
from you.  Your request for a file is only that the DOS or OS 
does all the nitty gritty work.  The OS like Windows is often 
referred to as a low-level program.

The programs that make the computer really useful run above 
and depend on the OS.  User programs use the OS to access the 
computer resources.  Your Mp3 player program makes is easy to 
pick the tune you wish to play you just click on it.  The Mp3 
program asks the OS to fetch the song file. The OS retrieves the 
file and puts it in memory and tells the Mp3 program where it is. 
You click on play the Mp3 player then interprets the data and 
requests the use of the sound card via the OS and the song plays 
for your enjoyment.

The OS spends more time accessing files than anything else.  
As the disk fills up and files are deleted and recorded, the 
OS may not be able to put a file all in one place.  The term 
for recording a file so that all data is in a row is called 
contiguous.  Many times the OS will break up a file and put bits 
and pieces of it in a number of places on the disk and create a 
list of where and in what order they are stored.  If files are 
recorded contiguously they can be retrieve with a single movement 
of the play head on the hard drive.  If the file is not 
contiguous (or, fragmented) the play head may have to reposition 
several times before retrieving the entire file.  As you might 
imagine this takes longer.  As more and more files are recorded 
in this manner the access time grows slower and slower.  The only 
cure for this condition is to rearrange the files so they ARE 
contiguous.

Windows has a sub-program or sub-routine for this.  It is call 
logically enough Disk Defragmenter.  It is located on the 
Programs list at Accessories in the System Tools folder. Periodic 
running of this routine will do wonders to speed up the operation 
of your computer. 

Marc Ready is the Principal of PCHelp, LTD, 
a Computer Consulting company and Developer 
of TATEMS Vehicle Maintenance Software at: 
http://tatems.com/