I think that the answer that barry has provided is different to what you're after.
The link shows you how to disable sign in with Google pop-ups on websites.
If it doesn't work, try the following:
Press and hold the following keys all at the same time:
"Ctrl" + "Alt" + "Delete"
Note it has to be "delete" and not "backspace"
On the screen that opens up, select "task manager"
On the tabs that run across the top, select "startup"
This will give you a list of programmes that start up when your PC boots up. Under "status" you'll see that some are enabled and some are disabled. See if there's anything in there for Google Drive
and disable it.
If that doesn't work, try:
https://ccm.net/faq/40964-how-to-remove-google-drive-from-startup-programs