oh, then the modems fine, your modem just isnt getting a cable signal.
Lights are:
The buttons are:
Power: Obvious, if this is off, plug it in

(if its blinking, its booting up, if its any color but green for any given time, call comcast and tell em to give ye another modem)
Cable: Status light, Solid green is what you're going for, tells you whether its connected to the network or not.
Status: Whether the modem is active or not, it will blink green when you're online doing things.
Ethernet: Connection between Computer and Modem. Solid green is your goal here to. if its off, can be anything between the modem, the ethernet cable, and the NIC on your computer.
Make sure the line from the modem to the wall is great (no cuts, securely connected, the wire in the middle isnt bent at the ends) you should have an entry point for the cable to go into your house (outside), make sure that dosent look damaged. if all of that is well, more than likely its on comcasts side, and as such, isnt your responsibility. (the only time they can charge you is if they come inside the house and do work(however if that box thats supposed to be outside is inside, they may or may not be able to charge ye for that, make sure ahead of time), so be careful on that, pricing is steep. around $100 an hour kinda deal)
no you were talking about your TV working great, and it will, the cable and TV signals are two different things, while you can get one just fine, the other can be broken. (more than likely this means the problems outside your house) but just check the things i told ye to anyway ^_^ (if ye pm me your area i can possibly find your local dispatch offices number for you when i get home, havent worked for em for a year but i believe the papers are still on my dresser)