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.
Trojan.Dialer.bty is a Trojan dialer program. Usually Trojan.Dialer.bty invades your system through browser security exploits or bundled with other malware. Once executed, Trojan.Dialer.bty will disconnect you from your dial-up ISP and reconnect you via an expensive toll phone number, resulting in a huge phone bill.
Technical details (How to remove Trojan.Dialer.bty(pop up))