Nuke Modified | AntiVirus Remover

What are these malicious contents?

Tell me the definition of what these malicious contents and what they do.
Adware, Spyware, Malware, Keylogger, Trojan Horse, Black Hat, Computer Worm, Rootkit, Greyware and Backdoor.
(I’m new to computers, and my friend told me these stuff and I don’t know these stuff, so help me out here, pls and thank you)

go on theses links to find out what they mean and what they do

http://en.wikipedia.org/wiki/Adware

http://enwikipedia.org/wiki/Spyware

http://enwikipedia.org/wiki/Malware

http://enwikipedia.org/wiki/Keylogger

http://enwikipedia.org/wiki/Trojan_Horse_(computing)

http://enwikipedia.org/wiki/Black_Hat_Hacker

http://en.wikipedia.org/wiki/Computer_Worm

http://en.wikipedia.org/wiki/Rootkit

http://en.wikipedia.org/wiki/Greyware

http://en.wikipedia.org/wiki/Backdoor_(computing)

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Trojan Horse $103.89 This book is in Like New condition