I seem to have the same problem. I installed my slingbox less then 3 mos ago, on 12/28/11. Last Sat all was working fine. On Sun - no TV. Called cable company, set up an appt, and today noticed that my Slingbox Pro-HD has no lights on. I've reconnected it, and TV worked (in green and yellow colors only) for about 1 min. Then the slingbox went dead again. I tried to plug it into another outlet - same story, only it lasted for less than a minute.
I am thinking about sending the box back. Because now I have neither sling nor TV
If you are not receiving any power from the Slingbox after troubleshooting, the issue can be caused by the power supply. Please contact our technical support department in order to get a replacement AC adapter. That should work.
My turbo pro-hd died within 1.5 mos of service. I did try 2 other power supply cords, different electrical outlets, and, upon suggestion of the tech support, connecting it directly to the router. Even though I purchased $50 extended care, I am opting for full refund (too many wires to connect and re-connect, separate payment for software to view my tv on my tablet (that's what I originally purchased it for) and shabbily made products just make it not worth it.