I bought the sling about six (so now support is gone) months ago. Going on a trip so decided to hook it up. Hooked it up per the instructions and the only thing I get is the power light blinks once about every 15 - 20 seconds. Actually I just timed it. Exactly 17 seconds, the power light "bleeps". With or without the ethenet cable connected.
Checked power, ethernet, connections to my DVR and all is good. Any suggestions?
It sounds like you may have an issue with your power supply, or possibly even your Slingbox. I would recommend you give our phone support a call and we should be able to find some resolution for your troubles.
Hope this helps,
The Slingbox Moderation Team