Maintain your PC
Just like a car, your computer needs maintenance. Fail to put air in the tires, check and change the oil occasionally, or keep fluid in the radiator and your car will stop working. Murphy's Law says this will happen at the worst possible time - say, on the Capitol Beltway in rush hour!
Your computer needs maintenance too. In most cases, the maintenance is to keep your protection systems and critical software up-to-date. These are what keeps your PC from being compromised by computer viruses, hackers, and spyware. Think of these as the road hazards of the internet, and if you don't protect your PC from them, your PC will stop working for you. Follow these links for more information:
If you don't maintain your computer, it may continue to work for you for a long time. But if not adequately protected, it may also continue to work for others - hackers, SPAMmers, and shady internet marketers. You may not care, but anyone you've ever used the computer to communicate with will - because they'll be targets for the bad guys using your computer.