Had similar problem setting up friends purchase recently:
• Full restart of your modem/router.
• Hard reset of your Slingbox
THEN full restart of computer
• Then try resetup again. This should shake off any previous settings it had, factory state, and should show up now...
It seems that you are having some issues with your Slingbox SOLO since you are not able to get the Slingbox ID.
The Slingbox ID is a unique identification number for your Slingbox. Since this is a second hand unit, I recommend you to reset your Slingbox and wait until it gets solid lights. The following links will provide you with the steps to follow in order to complete this process:
Hope this helps!