Badware is any staff that
is installed at computer against will of the administrator of the computer
or does things against the will of the administrator of the computer.
Hardware or software
The installation can be performed at the level of hardware (for example, at the
reparation of maintenance of a computer)
or at the level of the software, that can be performed as some modification of the operational system, replacement it to some surrogate,
or with some hidden setting, that refers to some programs, tools, that are designed work against interests of the main administrator.
Any computer with badware installed is qualified as corrupted. Many sites offers the special "antivirus" programs, that pretend to find and remove, replace, repair the corrupted elements in the operational system.
No evidences are observed in favor of hypothesis, that these "antivirus" programs provide the clean computer. No mechanisms, that prevent the fraudsters to declare their badware as an "antivirus" and distribute, pretending to fight against the badware 
The complete cleaning and reinstalling of the operational seems to be more efficient, than any antivirus programs (if the bugs are in the software).
- In the similar way, as agents of KGB, that is terroist organization (dangerous both for the people and for the state) pretend, that they provide some "security".