Chilled Windows is a harmless joke program on Microsoft Windows that makes the user think that their computer has a virus. It plays a fullscreen video in order to make its payloads appear real. In fact, it is actually based off the Nico Nico MAD of the same name created by どじょう, transliterated into Dojo which means "soil."
First, it will take a screenshot of the screen of the user and then flips it rapidly, along with tilting it diagonally and reduplicating it, all synchronized with the music, which is actually two parts of the "Nanairo no Nico Nico Douga" medley (the Hammer melody from Donkey Kong and "Red Zone" from Beatmania IIDX 11: IIDXRED). The screenshot then switches to an animated video that shows numerous error messages appearing on an edited Blue Screen of Death, also synchronized with the music.
However, it will not damage the computer in any way.