M4800 GPU upgrade - doesn't recognize Quadro M1000M

Hi,

I wanted to upgrade my old Dell M4800 from Quadro K1100M to M1000M (it's fully compatible).

So after installing it, Windows 10 recognizes it as Basic Display Adapter. I downloaded proper drivers for Win 10 64-bit but couldn't install them without disabling driver signature enforcement first.

So I modded the driver .inf file according to this guide (Nvidia INF driver modding (Guide) | guru3D Forums). I only inserted 2 strings: NVIDIA_DEV.13B1 = "NVIDIA Quadro M1000M", and %NVIDIA_DEV.13B1% = win10mobile, PCI\VEN_10DE&DEV_13B1.

After that installation went smoothly, and device manager shows Quadro M1000M. But that's the only change - there's still the message about error code 31 and no software detects the card. Can't run Nvidia control panel either as it says application is not compatible with the installed driver.

What could have gone wrong:

1) didn't mod the .inf file properly
2) the gpu is broken
3) some other issue

Would be really grateful for any suggestions on how to make that card work.

Thanks in advance.