If you are an avid computer user then more likely than not you are bound to have downloaded some adware, spyware or other unwanted "malware" programs on to your computer.

Read on, for I have tested out some free programs (ad- and spy-free) that will not only get rid of such malware for you but will also help protect your machine from getting infiltrated in the first place.

Malware is the general term for troublesome programs that insert themselves into your computer so as to occasionally display advertising (adware) or that track your computer usage (spyware).

Malware suck up computer power and eventually slow your machine down in addition to being intrusive and sometimes expensive annoyances.

Malware can also refer to or be referred to by unwanted dialers, which take over your Internet connection, or by actions caused by legitimate programs - such as the free versions of QuickTime, RealPlayer or Godzilla.

For example, have you ever tried to stop QuickTime from loading at startup or to get rid of RealOne Player's application scheduler?

It's almost impossible. Both programs are intrusive.

But sometimes that is the price you must pay to use them as they are both essential programs to have on your computer.

Dialers are among the worst form of malware.

These can be inadvertently downloaded when you visit an Internet site that you got to by clicking on a link from spam e-mail.

You will not know you have such a dialer on your system until you get a huge phone bill for calls that have been redirected from Bermuda through the Nigerian (or some other country's) telephone system.

How do you stop such programs from working?

It can be frustrating and once you discover you have malware on your computer, usually through the addition of a shortcut icon on your desktop or the sudden appearance of pop up advertising, the first step you should take is to try and remove the program through Windows' "Add/Remove" utility.

The malware may be listed there. Delete it if it is listed.

This may not work. These programs have a way of returning from the dead by hiding themselves throughout your system.

You can try removing the program from the start up list and see if it appears again.

Disabling some entries may prevent legitimate programs from working, and worse, for those who make a mistake, your computer may stop working.

For particularly vile programs you must now turn to the free programs created by groups of enthusiasts who have dedicated themselves to defeating malware.

Try SpyBlocker, which will mimic the Internet servers spyware use to access advertising. SpyBlocker blocks the spyware from calling out and then fools the program into thinking it has accessed the advertising.

Thus your legitimate programs are fooled into continuing to work. BHODemon, another program, scans your Registry for unknown Browser Helper Objects (BHOs), which direct adware to advertising.

Once these are found you can highlight a BHO in the list, and click the "Details" button to see whether you should disable it or not.

I have also tried SpyBot Search & Destroy which detects and removes spyware.

The software found 147 possible problem entries in my registry and system files.

SpyBot then gives examples of what companies are known to have used such files in their malware.

For example one entry possibly related to a dialer and has been used in the past by a company calling itself All-In-One Telecom, whose products include HotActionDating.

SpyBot is a very thorough program and comes highly recommended by other computer users.

Another program, SpywareBlaster, prevents spyware from ever being installed by tackling the ActiveX controls that are launched from a webpage in a bid to hijack your system.

At the base however only a good firewall, such as Zone Alarm (which is free), can protect your system in the long run.

A firewall will protect you from programs attempting to install themselves in your system and will also indicate when installed programs try to access the Internet without your knowledge.

All the programs and others not described here can be downloaded from a number of dedicated sites.

These are http://www.answersthatwork.com; http://www.cexx.org and http://www.spywareinfo.com. Such sites also give advice on how to deal with some of the annoying behaviour of programs such as RealPlayer and QuickTime. Happy hunting.

Tech Tattle deals with issues in technology. Contact Ahmed at editor@offshoreon.com