It’s a bit hard to tell from the pictures, but this does not look right to me.
The GTX 660 Ti is specified with a power draw of 170W and consequently has two 6-pin PCIe power connectors (designed to supply up to 75W each), on the top. The rest of the power is supplied via the PCIe slot.
It appears one of these connectors is hooked up to what looks like an appropriate PCIe power cable. The other one, however, seems to be connected, via a converter, to a cable with Molex connectors. Traditionally, Molex power connectors were used by hard disks. A hard disk draws about 6W these days. I don’t know how this cable is supplied by the power supply unit, but I would assume it is not designed to supply up to 75W (and that assumes the converter works properly with regard to different voltage wires).
The other thing I notice is the cooling solution. A GTX 660 Ti is supposed to have a shroud that forces the air from the fan on the card across the heat sink vanes. There is no shroud here: I see the exposed heat sink. Did you install a water cooler block instead of the standard heat sink? But I don’t see any piping that would suggest water cooling. Without proper cooling, a GPU cannot work. Usually it shuts itself off to prevent permanent damage due to overheating.
Where did you acquire the GPU in this condition, and who installed it? It seems both power supply and cooling of the GPU have been compromised, to the point where the card is at present inoperable and possibly even defective.