After scams, frauds and viruses, the next biggest scourge of the internet is spyware.
Spyware can find it’s way onto your computer system through a variety of means.
Commonly, this occurs when you download and run games, toolbars, screensavers, etc.
Spyware can also find it’s way in through normal web surfing.
The purpose of spyware is to use tracking cookies in order to identify your surfing habits.
This in turn can be used with adware and other malware that has found it’s way onto your system in order to serve adverts to you.
Often this is in the form of annoying pop-ups but sometimes it has been known to even change the words displayed on your screen whilst surfing the web.
In such cases, perfectly innocent sites end up showing you hyperlinked text to some very dark and dubious corners of the net!
After a while, the amount of spyware and malware that can accumulate on a system is immense.
This has the effect of slowing down the surfing experience, sometimes to a crawl.
If you search around the net you will find many solutions being offered.
Some need to be paid for whilst others are free.
The free ones will generally clear your system to a degree but, as with anything in life, you get what you pay for.
Here are some of the better Spyware and Virus removal tools -

{ 3 comments… read them below or add one }
I use ad-aware(free version) but it misses loads of stuff. Am I using it wrong or do I need to get the paid version?
That’s a good addition to the list Jhen, I had quite forgotten Spybot Search and Destroy. It’s definitely one of the better solutions on the market and it’s free
Spybot’s among the best free spyware removal tools there are. Look for Spybot-S&D (search and destroy).