Go to your Google Account's third-party connections page. Select Linked account. Select the third-party app or service whose connection you want to delete. Tip: If you have more than one connection type with that app or service, this connection appears under “Google has some access to your {App name} Account.”

To sign in to your Google Account (or any Google product): Go to the sign in page of the product (for Google Accounts it is myaccount.google.com). Enter your Gmail username (everything that appears before '@gmail.com'). Enter your password.

Go to http://accounts.google.com/signin/usernamerecovery and enter any email accounts or phone numbers that you've had for a while and which may have been used as recovery info. The “find your email” page can help you locate any forgotten Google accounts.

On your computer, go to Gmail. Enter your Google Account email or phone number and password. If information is already filled in and you have to sign in to a different account, click Use another account. If you get a page that describes Gmail instead of the sign-in page, at the top right of the page, click Sign in.