1. The keyboard is mightier than the mouse. - There is a reason why the keyboard came before the mouse. This is among them. There are plenty of shortcuts involving the keyboard. The main reason they are called shortcuts is because it saves you the trouble of moving the mouse to access them. There are things at which the mouse is better, but in many cases, mastery of the keyboard will lead to a most comfortable computing experience.
2. Have the emergency key shortcuts at your disposal.
- All operating systems usually have a shortcut to save the operating system from crashing completely in the case of some awful program or some terrrible execution somewhere. In Windows, this is usually the ever popular Control+Alt+Delete. In Mac OS X, it's usually Command(Apple)+Option+Esc. In Linux, I think most desktops use Control+Escape.
3. Computers can fail, and probably eventually will.
- Computers have a lifespan of about 5 years before becoming impossibly obsolete to some people. I myself have survived with a computer for a number far surpassing that, and I have no intention to ever let it happen again. That computer didn't fail during my active usage, but it soon did after about a year or two after I finally got an up-to-date computer.
4. Since computers will fail, backup often.
- The part with the longest warranty after RAM is probably either your processor or your hard drive. Chances are however that your hard drive will fail eventually after the warranty period. I have not seen a hard drive last more than 10 years in my home, and many have failed within the warranty period itself. I carry out a pretty thorough backup regime, although it has become patchy with the advent of more reliable hard drives. There is now about three copies of each of my university work and notes which are stored electronically, all up-to-date. It will not be long before I make a fourth into a piece of significantly more reliable storage media.
5. The essentials of computing: monitor, keyboard, mouse, Internet.
- Every basic computer should have a monitor, keyboard and a mouse. Internet access isn't vital yet, but without it, your computer's potential is wasted. Heck, even my PSP can get Internet access. It is not vital, but if you have it, the whole world is there. :D