Adware is similar to Spyware, a malicious software/programs installed into your computer without prior notice.
It happens when you install a software contains an adware, downloaded some files such as free games, free software, free music, ringtone, videos and more. An adware can also installed into your computer together with a free software that you previously installed.

These malware is rapidly growing and infecting many computers from around the world.
Compared to a spyware, an adware is harmless. It only generates popup banners and advertisements on your computer.
Although it is harmless, but for some people it is annoying.

How to prevent an adware ?
Avoid downloading softwares from untrusted sites, avoid downloading games, videos, musics from an untrusted vendors.
Read the user agreement when installing software, particularly a free software.

Cleaning up your computer from an adware.
First, you need to have an anti-adware programs. You may download from many trusted vendors such as AVG Technolgoies, Kaspersky, Symantec, and many more.
Second, install the software by following the installation wizard. Third, perform a complete scan on your computer.

After all the steps above completed, you need to recheck the security level on your computer. It should at least set into medium level to protect your computer from unwanted downloads.

Spyware is a malicious software or some people call it malware that placed into your computer without you even realize of its existence. You would probably wondering how can it get inside your computer.
Well, this can be happen when you visit an online game site or a website that offers a free softwares, videos or musics. When you’re done downloading, the spyware also gets downloaded into your computer.

These days, spyware have infected millions of home computers. Spyware is tracking your online habits. What sites are you visiting, what products are you searching through the internet. Some spyware also capable of logging the keystrokes that you have made, every bit of information you enter to fill out a form, for example your name, address, credit card information. Then, the information collected by this spyware is sold for a business purpose, or even worst it can lead to an identity theft. Another problem with a spyware inside your computer is that it slows down the performance of your computer.

To remove a malicious software you need to have an anti-spyware prorams, many trusted vendors provided this programs free of charge, such as AVG Technologies with their AVG Free Edition, Spybot – Search and Destroy, and many more.
You can simply download the programs, install it on your computer. After all the installation steps completed, then you may proceed to scan your computer. You may need to double scan your computer using a different anti-spyware program just to make sure that your computer is clean.
Once the scanning progress completed, you should reboot your computer, and perform scanning once more, just to make sure there are no “ticklers”. Ticklers is a mini program that can reinstall a deleted file.

The best way to prevent spyware is to download only from a trusted vendors, avoid opening an unsolicited email, when downloading software read the agreement carefully.
Sometimes when you download a free software the agreement will state that they are also installing a software that acts just like a spyware, this way you will have the full control whether to allow or deny such software to operates in your computer.