Did you flash the system BIOS or the GPU vBIOS?
My guess is that it could have the wrong vBIOS so you may need to try a few from TechPowerUp
Recently, my gtx 765m graphics card in my alienware 17 burnt out. I bought a 980m as a replacement for it. While it was shipping, i did a factory reset on the computer, upgrading it to windows 10. Installed the card, works fine, but noticed it would quickly overheat, leading to a massive drop in performance. Upon inspection, the GPU fan wasn't running at all, causing the card to overheat. After flashing the bios, running HWINFO64, updating GPU drivers, and even buying a new fan, it still wont turn on. It will, however, work for about 1-2 seconds on startup, and, after flashing the bios, will now show up in the diagnostics menu when you boot it up. Despite running during the tests, it states that the fan is running at 0 rpm. i can't get the fan to spin in HWINFO64, only the CPU fan works. I'm unsure of anything else it could be, but nothing I've tried has gotten it to function. Any help would be greatly appreciated.