Happiness Anti Joke Unwanted Toolbars Backdoor - Version 1.3.62 Happiness Anti Joke Unwanted Toolbars Backdoor - The term rootkit is used to define a Trojan (or technology) used to hide the presence of a malicious object (process, file, registry key, network port) from the computer user or administrator. Removing rootkits without compromising system integrity is particularly challenging and needs to be done with care.