The ten steps to a happy PC are:

know your PC!
organise your data
keep in tune
create a rescue disk
backup data as required
watch out for viruses
keep up to date
don’t mess with programs
clean regularly
shut down correctly.

Step 1 – know your PC.

The first preventive step you need to perform is to take an inventory of your computer system. This information will be vital if you later have to contact technical support or have your system serviced.

Make a note of your serial number and model number. With this information, your system manufacturer can determine the components of your system. If you've added components to your system, note the model and version numbers of the components. You'll find this information in the documentation that accompanies add-on hardware.
Beyond these basics, you need to get details of your system's configuration. On Windows PCs, this means copying and printing a few important system files (AUTOEXEC.BAT, SYSTEM.INI for example) that will come in handy if you later have a problem or need to speak to a tech-support person.

With Windows XP/2000, you can go into Accessories, System Tools, System Information to find and print this important data.

For earlier versions of windows run the Sysedit program. With Windows 95/98/ME, click on Start, RUN, type SYSEDIT in the blank window, and click OK. It will bring up all your system files -- from AUTOEXEC.BAT to SYSTEM.INI -- in Wordpad windows. From there, you can save them and print them out.

Step 2 – organize your data.

You have lots of reasons to keep the files on your hard disk organized. First, it makes it easier to do "housecleaning" -- deleting files you no longer need. Second, keeping data files in their own well-labeled folders reduces the risk that you will inadvertently delete an important program or data file. A well-organized hard drive is easier and faster to back up. Give files and folders names that will make sense even after you've forgotten why you created them.

In addition to organizing your files, at least every two months you should delete files you no longer need. A disk filled to within 5 percent of capacity is more prone to errors -- and a lot slower -- than one that is not so chock-full.

Step 3. – keep in tune.

Because it is the place where you permanently store your applications and, more important, the data files you create with those applications, your hard disk requires special attention to keep it operating at peak efficiency. Disk scans for "lost" files and bad sectors will prevent most disk problems before they occur, while running a disk defragmentation utility will improve the performance of your system.
Every day, you create new files, delete unwanted ones, and write updated versions of current files to your computer's hard disk. Because of the way Windows assign disk space to files, your hard disk can become fragmented over time (i.e., your files get placed in pieces all over the hard disk, because there is no one space large enough to hold them). A fragmented hard disk slows disk access and makes it harder to recover from disk errors.  (See earlier article on disk defragmentation or email me for a copy).

Step 4. – create a rescue disk.

If your computer develops a problem that keeps it from accessing your hard disk, you need some other way to boot your system. The answer is an emergency boot disk. With XP you may be able to boot directly from the XP CD-ROM, but consider using something like AVG to create a specific rescue disk for your system.

Step 5 – backup your data

Backing up your files simply means making a copy of them so that if the original is lost or damaged, you can use the copy. You can back u