I might suggest going through the TV's Plug and Play option in the Setup Menu. That should effectively reset the television. I might also recommend unplugging the devices from the HDMI ports first, and then seeing if connecting them helps.
There's always the option for a repair if you're still in warranty. Registering on the Samsung.com site, if you're 3 months out of warranty will extend the warranty period for U.S. customers.
You can do that here:
Warranty repairs are also available through 800-SAMSUNG in or out of warranty, but if the set is out of warranty, then the repairs will not be covered by Samsung.
I hooked up all my HDMI sockets with TV/cable, DVD and media player and they were working fine for the past few months. All of the sudden, 3 of my HDMIs stopped working on me. The remaining one is linked to the TV/cable box and it is working fine. I tried to connect the only working HDMI cable to another HDMI socket and it did not help. The socket recognized the HMDI cable but said no signal. I switched back to the original socket and it would work fine. I also tried to reset the tv by holding the "EXIT" button but no response. Probably due to different model. Can you help?