These are usually anti-spyware or security software applications that use various forms of deception and/or unethical means or show a history of negligent false positives to goad the end user to make a purchase.
In some cases these applications maybe downloaded with some form of unwanted software at which point the rogue application is offered to the customer as a way to remove the unwanted software.
This is a rogue antispyware application that is part of a trojan payload. When visiting certain security related websites, users are prompted to download Ultimate Defender thinking that it is related to the security sited visited.
Attempting to use the online anaylzer in X-ray PC brings up a seemingly related window. This prompts the user to install Ultimate Defender.
This is the program installed after the hoax installation of the latest X-ray Pc executable. Please note the lack of options the user has in closing the program. Video capture shows that the only way to prompt out of buying their program is by Ctrl + Alt + Del and ending the correct task.