I'm sorry to hear you are having problems with setting up your Slingbox! I'd like to ask you a few questions to help you our further:
Are you trying to run through setup from the Desktop application?
Exactly which Legacy Slingbox are you trying to configure?
Have you attempted running through setup from Setup.slingbox.com?
And to clarify about resetting the Slingbox, you actually have to hold down the reset button for a full 30 seconds for a factory reset to your Slingbox. Answering these questions will really help us out in resolving your issue in a timely manner.
The Sling Media Moderation Team