Comcast

Update.-- After calling Comcast they added a new set of instructions, but be careful when you call them as they will reset the box which erases all the channel information and has to be reloaded. But here's some suggestions I learned before you call them.

First, as noted, disconnect the cable to the box from the outside and reconnect it. If that doesn't work then unplug the HDMI cable on the back of the box to the TV (mine has a HDMI to DVI cable for the older Plasma TV's). This should help, maybe. If not, see second.

Second, and the next to last resort, unplug the box for 10-15 seconds. This will erase all the information in the box, same as above but their reset is slightly different. If that doesn't work, then call Comcast (first write down the serial number of the box found on the back) and be prepared to repeat the steps you've already tried. If that doesn't work, see third.

Third, the obvious ask for an appointment to replace the box. And remember not to be so mad at the service representative as they only work for the company, they're not the company to be angry about.

Original Post.-- I wish my area had real competition for cable subscribers who have Comcast than the two satellite companies which aren't any better or better priced once past the new subscriber discount period. They were told to unbundle channel packages to give customers choices of individual channels, but they've just ignored that to keep bundling channels to force you to buy bundles for the variety of channels you want.

The worst service is when movies begin to pixelate and stop they give you some instructions to "improve" it which ends up makes it worse where you lose not just those channels but a lot more with black screens and the little box, "This channel should be available shortly", for longer than the movie and any news show. 

In short, you're paying for non-service. I'd say they suck, but that's giving them too much credit for their service but would for their prices and your wallet. 

If you're wondering their instructions are to disconnect the cable to the box, at the back of the box or at the wall, wait and reconnect them. This often solves the problem as the bandwidth is overloaded. If that doesn't work, turn the box off and back on. This resets some of the box and saves all the settings and information but doesn't really do much.

The nuclear option is to unplug the box, wait 10-15 second and plug it back in. This completely resets everything except what only they can to from their computers, which is also an option if you want to call and wait for the next representative to explain they'll reset the box manually. Either way, sometimes it works and sometimes it doesn't, which leaves the obvious, call for an appointment.

Yeah, they create problems only they can fix. Sorry, Comcast, you've never solved some of my problems  with your software an latest generation cable boxes and the digital audio signal (doesn't work), and you just seem to create new ones, trying to do too much down with too little cables, and always at the most inconvenient times.