Here is where you can download all your Laptop drivers including VGA (Windows 8.1/10): laptops and netbooks :: lenovo b series laptops :: lenovo b50 45 notebook Lenovo PC Support - US
It is recommended to install Lenovo's VGA driver since it is 100% compatible with your laptop. First install Lenovo VGA Driver and see if it works the way you want. IF it does, then install AMD Generic laptop driver and see if it works the way you want.
Here is how to install AMD Laptop drivers:Laptop graphics update...How to and how to make your laptop Switchable with two GPUs: Configuring Laptop Switchable Graphics on a Windows® Based System | AMD
Found this Lenovo Forum concerning B50-45 Switching issues with your laptop model: Lenovo B50-45 Switchable Graphics Problem - Lenovo Community
This Lenovo Forum on B50-45 with HD8500M where HD8500M is not recognized could be the same problem you are having: https://forums.lenovo.com/t5/Lenovo-B-and-G-Series-Notebooks/Lenovo-b50-45-won-t-detect-my-r5-m230-v...
You need to download the APU (CPU with Integrated R4 Graphics) Driver. This will install both the R4 & HD8500M Drivers for your GPUs in your laptop.
Since you didn't mention the APU Processor you have you need to go here: AMD Drivers and Support for Radeon, Radeon Pro, FirePro, APU, CPU, Ryzen, desktops, laptops and choose the correct Processor and download the APU driver.
Please next time you answer, translate it into English since this is an English Only Forum. Thanks.
