I understand that your having trouble getting your Slingbox SOLO to reset back to factory settings. This article, How to reset your Slingbox to factory settings should help with this.
If you need further assistance, please feel free to contact us, this link, Contact Sling Media Support provides information on how to do just that.
If you are located in the US, just call 877-GoSling (877-467-5464).
Hope this helps.
Sling Moderation Team
Good morni superatim
The issue was related with the power cable connection.
I contacted the support service and they sent to me a new one.
By the way the support guys are as good as I never experienced with any other provider.
As soon as I put in place the new cable the sling box started as good as new.
I hope this help.