I had the same issue and discovered one of the keypad buttons stuck just a little bit under the remote cover. The way the remote "thinks", that button is constantly being pressed, which is why the Cable light stays on. Once I freed the stuck button, everything returned to normal.
Thanks for the troubleshooting tip. None of the buttons seemed to be stuck. I went through all the buttons with the batteries out and all of them seemed to be working normally. I guess I'll stop by Comcast today to exchange it.
Thanks for the information. The remote is the silver one with the grey OK/Select button. I had the batteries out overnight and had no luck with it rebooting. I also tried the reset in the link you sent me and I wasn't able to get to the point where pressing the setup key had any effect. Again, thanks for the tips.
I had the exact same symptoms you did last night and I tried everything to fix it. Then I noticed a stuck up arrow key. It was stuck under the metal ever so slightly I had a hard time seeing it. I freed up the key and it started working like a champ. Try closely checking your remote for a slightly stuck key. I hope this helps you.
My remote is not working. I removed the batteries and put them back in to try to reboot the remote without luck. I also have tried fresh batteries. All I get is the cable light (on the remote) blinks twice and then the TV light starts blinking without stopping. I really don't want to go to the Comcast office to exchange it. This is becoming an every-four-months occurrence.