Thank you for using the answers forums. We are sorry to hear that you are having issues using your Slingbox. The Slingbox ID is actually not available until the Slingbox is fully set up and not actually needed for the setup. As long as you are using a computer with a supported operating system and browser, you would visit the website setup.slingbox.com and will be able to locate the Slingbox and complete the setup. Please refer to these articles below if you need more help.
The Sling Moderation Team