Spyware
Spyware does what it says. It spies on you. It can monitor your activities, surfing habits, credit card information, passwords etc. and send this data back to a central location so some unscrupulous people can use this data.

Unlike adware, spyware usually runs silently in the background without making you aware it's there. Obviously the longer it goes undetected the more information it can retrieve from its victims.

Spyware is a very serious risk and should not be taken lightly. Once an attacker has got your personal details such as credit card information, passwords for online banking etc. you stand a very real chance of identity theft and financial loss.

Adware
Adware is generally used to force adverts in front of you. It will monitor your surfing habits and when you visit a site it recognises it will force a relative advert or pop-up.

Let's say you visit a site that is selling second-hand motor cars. If the spyware recognises the site you are visiting it may well force adverts in front of you that are relative to that site. For example car insurance, vehicle recovery services etc.

Other types of adware just force advertising in front of you whether it is relative or not. P*rn sites are of common use and can pop-up at the most inconvenient of times (usually when the wife is standing behind you) !

Some adware will change your home page, add links to your favourites, add shortcuts to your desktop. Not such a major security risk like spyware. But it can become extremely annoying to have adverts popping up when you least expect it and having to constantly change you home page.

Malware
Malware is short for 'malicious software'. It is designed to destroy data on your PC or cause havoc on a network. Trojans, viruses, worms etc usually fall into this category. Obviously a major security risk and the results can be catastrophic. Unless immediate action is taken to remove you will more than likely lose some, if not all, data on your PC. It's not uncommon to have to completely reformat a hard drive to remove them.

How Did I Get Infected?
There are umpteen ways it could have happened. But here are a few of the most common:

• Attachments sent in e-mails.
• Downloading free music.
• Downloading free utilities.
• Installing untrustworthy software.
• Visiting certain types of websites (p*rn, warez etc.)
• Installed when using instant messaging services.

Iain Williams is the owner of Spyware-Aware.com which gives free advice and reviews of spyware removal software.