Those who make computers their career – programmers, Web designers, technicians and the rest – obviously have less “computer issues” than most people do. What may not be as obvious are the reasons why this happens. They may be simpler than you think. By following a few common sense rules, the quality of the time you spend on the computer, for business or for leisure, can improve significantly, your productivity can grow and you can eliminate substantial hassles.

In this article, we'll take a look at one simple way that can help you avoid some common issues that affect today's computer users: loss of performance, errors, “crashes,” spam, invasion of privacy and identity theft, all caused by seemingly harmless and useful things that we voluntarily download from the Internet.

We all enjoy customizing our computers, lending them a drop of our personalities. We often do this through our use of customized screensavers, wallpapers, cursors and icons, to name a few. Also, there are many apparently handy “utilities” (desktop weather programs, useful toolbars, fancy clocks, etc.) that many of us use. While there is nothing inherently wrong with using all these things, a lot of caution should be exercised as to where they come from and what else might be in the package. That adorable little butterfly cursor you just downloaded might just be the carrier of other software, possibly intending to track your online activities in order to serve you advertising based on your interests, use your computer to send itself to others, log your keystrokes (usernames and passwords included) and send them to its maker, dial a pay phone number from your phone line or inundate you with pop-ups, at the same time draining your computer's resources. How do you avoid all this?

Check Your Sources

One of the things to keep in mind if you wish to keep your computer safe from what is usually referred to as “malware” (viruses, spyware, adware, etc.) is that you should never download anything from sources that you don't trust. It's one thing to download a screensaver from NationalGeographic.com or ComedyCentral.com versus downloading screensavers from JoesScreensaverEmporium.com. Using reputable sources translates into an extra layer of security.

That, however, is not to say that small websites don't provide good and harmless downloads. Indeed, the Web is full of small, legitimate websites that offer more downloads than large, corporate websites ever could. But make sure you research the specific website from which you are tempted to download something. You can search information about it in Google and see if there are any complaints. If others have had any issues with it, you will usually easily find their objections on the Web.

Avoid Certain File Types

The second thing to remember is that there's almost no legitimate reason for a cursor, wallpaper or screensaver to be packaged as an executable file. That is, it should almost never come as a download with the extension .exe. The extension is the last group of characters (usually three) after the last dot (.) in the name of the file you're downloading. Extensions are always the last part of the file name. Every time you download something (by either saving the file on your computer or “running” it), your browser should show you the extension at the end of the file name that you are downloading.

Remember that there are legitimate .exe files. Most of them are. But make sure you trust the source of your download before getting anything with the extension .exe on your computer. The same applies for compressed files (e.g..zip, .rar, .gz, .iso, etc.)

Here are a few file types that should be safe to download: .jpg, .jpeg, .gif, .png (all for images), .scr (for screensavers), .ico (for icons) and .cur (for cursors).

Follow these tips and you will greatly reduce the chances of enthusiastically infecting your computer with unwanted software.

Never Use the “Useful” Toolbars

Well, almost never. There are some toolbars that are actually useful and that you could use if you're not worried about wasting computer resources. If you have a powerful machine, you shouldn't lose any sleep about the resources a toolbar is using. They're insignificant compared to the total capacity of your computer. If, on the other hand, you're experiencing low performance and slow speed on your computer, it would probably be a good idea to uninstall any toolbars that you can live without. The last thing you need on your overworked and under-equipped computer is a charming toolbar that further drains it of its resources. Same applies for all other programs that are not necessary to you. Keep it down to the bare necessities and your computer will reward you with improved performance.

Of course, just as with other programs you get off the Web, you should be extremely cautious as to where they come from. Yahoo's or Google's toolbars will probably only slow you down and take away from your screen space. There aren't any other dangers to using toolbars from reputable Internet companies, if you don't mind that some of them (for instance, Alexa's), anonymously track your browsing activities.