I had just reinstalled windows 7 after having had windows 8. the computer was not recognizing my GTX580 card and when i tried to install the drivers for the card installation would fail. In an effort to check that the cadr was seated properly, i accidentally loosened the power cable to the card. This caused my pc to shutdown and try to restart. now when you start it up, it will post, and try to start windows. windows will fail to load. you then have the option to try to repair windows, but it keeps failing. even my old windows 8 install from another drive will not load properly. the fail - fix - reboot cycle is continous and i have not been able to bring my pc back from the dead.