Sometimes Google Drive links are missing from Windows Explorer. There is guide how to add these again. 

Google Drive in Navigation Pane - Add or Remove in Windows 10
How to Add or Remove Google Drive in Navigation Pane of File Explorer in Windows 10
https://www.tenforums.com/tutorials/48991-google-drive-navigation-pane-add-remove-windows-10-a.html


Adding Google Drive to the Windows Explorer sidebar
http://luke.digital/adding-google-drive-to-the-explorer-sidebar/