I bought an old GPU and I'm trying to flash it.

[Lounatic]

So I bought an old Gainward Phantom GTX760. It won't install drivers, as it would just crash or go black and go back. I watched a JayzTwoCents video where he flashed a 780ti and I had the same symptoms as his card minus the messed up booting. I looked at the GPU info in GPU-Z and all it had no info on the bus width, VRAM, and the bandwidth. I tried flashing the GPU with NVFLASH and tried to turn off the EEPROM protection but it just doesn't do it and sends me a message saying, "set EEPROM protection function failed." I tried not touching the EEPROM and went straight into flashing it but it won't allow me. I got an error code saying, "Falcon reset control is disallowed! A system restart might be required before running the utility." Am I doing something wrong? Is my card just unsalvageable? Thank you!!