Download all needed drivers from the lenovo site, and install them in the right sequence.
And a tip: when everything works, make a recovery drive, as recommended by Microsoft in https://support.microsoft.com/en-us/help/4026852/windows-create-a-recovery-drive . You can use it to do a clean install of the system as it was when you made the drive. That's much better than a generic install like you probably did now.
I have a Lenovo Yoga 2 Pro model 20266. I had to do a clean install of Windows a few days ago. The computer was acting up so badly I wasn't able to use the built in recovery options or create a restore point and had to do a clean install of Windows 10 from a USB. I had to format the Windows partition to do it. (D drive still intact.)
Anyway, now I have noticed two problems:
1 - The built in fans no longer work. I downloaded a fan checking tool and the computer doesn't appear to be detecting the fans at all. They are completely clean and worked fine up until the reinstallation. The computer just doesn't detect the hardware.
2 - I am not able to adjust screen brightness or automatically rotate the screen like I could before. I checked in device manager, and my monitor is showing up as "PnP Monitor Lock." I tried manually updating/installing the Generic PnP Monitor and Non-Generic PnP Monitor without luck. The system just doesn't seem to be detecting the hardware right.
Anyone got any ideas?

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