Log in to your Salesforce account.

Once logged in, you should see the URL for Salesforce in your browser's address bar, which should look something like this: https://[YourInstance].salesforce.com/home/home.jsp

In the URL, replace everything after 'https://[YourInstance].salesforce.com/' with the Salesforce ID of the lead you're searching for. It should look something like this: https://[YourInstance].salesforce.com/00QMl027993Ml5VlOPWC

Press Enter or Return to navigate to this new URL.

You should now be viewing the lead record associated with the provided Salesforce ID.