Question: I've dual booted my windows 10 laptop. After installing UBUNTU 20.04 LTS, it can't detect the NVIDIA driver. Though, windows os still detects the driver. I've installed nvidia driver, but it's not detected.

I've tried `sudo ubuntu-drivers devices`. It doesn't show anything. At **Additional driver** section in **Software & updates** apps,

> 
> No additional drivers available
> 
> 
> 

is shown.

All in all, UBUNTU 20.04 LTS isn't detecting the NVIDIA driver for unknown reasons.
Please, help me out.

My NVIDIA Graphics card: Geforce 820M

I've attached the output of `lspci -k | grep -EA3 'VGA|3D|Display'`

```
00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09)
    Subsystem: Hewlett-Packard Company HD Graphics 5500
    Kernel driver in use: i915
    Kernel modules: i915
--
09:00.0 3D controller: NVIDIA Corporation GF117M [GeForce 610M/710M/810M/820M / GT 620M/625M/630M/720M] (rev a1)
    Subsystem: Hewlett-Packard Company GeForce 820M
    Kernel modules: nvidiafb, nouveau, nvidia_drm, nvidia
0a:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter

```

Answer: 
Similar ([How am I supposed to use nvidia-prime?](https://askubuntu.com/questions/661922/how-am-i-supposed-to-use-nvidia-prime))
When I switched to Intel the Nvidia settings disappeared and to bring them back you need to

**sudo prime-select nvidia**

The prime-select has some other useful commands:
prime-select nvidia|intel|on-demand|query

This didn't work for me either
(<https://dev.to/simonpham/how-to-fix-ubuntu-nvidia-driver-is-not-loaded-2ipp>)

For a full explanation that worked for me see (<https://www.linuxbabe.com/desktop-linux/switch-intel-nvidia-graphics-card-ubuntu>)

I'm on Ubuntu 20.10 but the same thing happened on 20.04 and I upgraded to 20.10 but it was exactly the same issue.
If all the steps above don't work, and you are dual-booting between Windows...then just boot Windows and then reboot into Ubuntu. Windows might have been doing some updates that may have messed with the NVIDIA card from what I can tell. I do all of the above and it didn't work until I booted Windows.