Spyware, Adware, and all Malware - Kiss It Goodbye

They are used by hackers to capture your keystrokes, where sensitive data like credit card numbers and passwords are targeted.  The programs often slow up your computer, even to the point where the mouse moves slowly across the screen.  They are a nuisance and a big security threat that can end up affecting far more than just your experience sitting in front of your computer, but your bank account as well.