Lenovo W520 not detecting SDHC card and also won't show in Device Manager in Windows 10

To sort this, the solution that worked for me was:

1) Go to Drivers & Software Section of W520 in Lenovo Website

http://pcsupport.lenovo.com/in/en/products/laptops-and-netbooks/thinkpad-w-series-laptops/thinkpad-w520/downloads

2) Under - > Camera and Card Reader

A) Download & install

Ricoh Media Card Reader Driver for Windows 10

B) Restart the computer

C) Download & install 
SmartCard reader driver for Windows 10 

3) The Card should work now & Ricoh SD Disk Device should also show under Disk Drives in Device Manager.

Windows 10 device manager keeps refreshing

For me the problem was Logitech Wireless mouse. Every time i move the mouse, Device Manager refreshes. Don't know if this is normal.

So while working in Device Manager, i used my Laptop Mouse Touch Pad instead. Then it won't refresh.