Why is the PC unable to detect PCI Express board on the FPGA development kit in Windows® 10?

You may see the PCI Express driver has been installed successfully, but it doesn't show up in the Device Manager.
This is because the PCI Express driver that comes with our FPGA development kit is not signed for Windows® 10. Windows 10 requires all drivers to be signed by default. 

Follow the steps below to disable Windows® 10 driver signature enforcement and install the driver. 

1. Click the Start menu and select Settings.
2. Click Update and Security.
3. Click on Recovery. 
4. Click Restart now under Advanced Startup. (The computer won't actually restart until after step 8.)
5. Click Troubleshoot. 
6. Click Advanced options.
7. Click Startup Settings. 
8. Click on Restart. 
9. On the Startup Settings screen press 7 or F7 to disable driver signature enforcement.
10. Follow the PCI Express driver installation instructions in the FPGA development kit document.