Adware:Adware (or spyware) is a small program that is designed to show advertisements (in various form and degrees of intrusiveness) on your computer. It often reports personal information back to its owners. As a result your sense of privacy can be violated.
Messenger Stopper is an adware application that shows unexpected commercial pop-up advertisements. The threat also silently contacts certain remote web servers. Messenger Stopper must be manually installed. It runs on every Windows startup.
Technical details (How to remove Messenger Stopper(pop up))