Your computer may be infected with spyware!
How often do you come across a popup like this:
If you come across anything like this NEVER, EVER, EVER click on it! Never trust that a button or link labeled as CANCEL actually means cancel. In the world of adware and spyware, NO very often means YES. In fact, everything means YES or at the very least nothing works as it should. The Windows within a windows trick (shown in the image above) is a popular one for getting people to click on the page by trying to drag the windows by the wrong title bar and beginning an installation process or diverting to another site.
Close any boxes like this using the key combo ALT and F4 - that will make it go away and go away safely!