My dryer was working fine for the past 6 months. About a week ago, it continued running when I opened the door. Now it doesn't work at all, and the indicator light doesn't turn on. I checked breakers and unplugged it... Any suggestions are very welcomed.

Here are some manuals: https://dl.dropbox.com/u/8010163/Whirlpool%20Dryers.zip
It sounds like the first problem is due to a bad door switch. Replace that if it tests closed with meter when it's supposed to be open. Here's how to use a meter: https://dl.dropbox.com/u/8010163/Whi...e%20Manual.pdf
You MUST use a meter when diagnosing an electrical appliance-We don't have x-ray vision.
As to your problem now: Most likely it is dirty and lint deposits have built up, as it always does, in all the air ducts which will cause the main safety to blow.[B]You need a multi-meter to find which safety has blown.[B] You will have to take it all apart and clean the drier out thoroughly or it is all for nothing. Every air duct will have to be removed and scraped and washed out to remove baked on lint deposits which bakes on like a concrete lining. This will burn so the manufacturer has installed the safeties to keep from having a house fire. The safeties are oval-shaped with a round center part containing the safety with two plug-on terminals for the wires and when they burn open, from the dryer being dirty, nothing will work or it will not heat. Using an ohm meter you put a lead on each terminal of the safety, with one wire unplugged, and if it is good you will have a reading of about zero; if it is bad it will read infinity. Driers were the number one cause of fires at one time, hence now we have safety fuses. Look at: How to clean your clothes dryer. How to make it hot again. - YouTube to see how. Also look at these to get an idea about how to clean it: Mr. Appliance Tips: How to Clean Your Dryer - YouTube ; Cleaning a Dryer Vent and Lint Trap - YouTube
Electric Clothes Dryers Dryer vent cleaning prevents fires - YouTube and: Cleaning out a dryer with top lint cleanout - YouTube
Cleaning out a dryer: By a woman 2 of 2 - YouTube
When you finish cleaning the drier it is best to also replace the belt, too, because you do not want to have to disassemble it all over again and if the belt is over two years old you should replace it.

Note that on most of the videos it does not show them washing out the parts, but this is important because it's the only way to really get the parts clean, just don't get motor wet or the capacitor if it has one. Vacuum out the motor to remove all dust. I would move the drier out to your garage to have plenty of space to work. You also want to check your vent and clean it, also. The vent should have a short run and be straight as possible. The job is really easier than it sounds. There is no shortcut that will work; it has to be cleaned well. Before you re-assemble it make sure to use white lithium grease (high-temp grease) and grease all bearings. Just vacuuming out the dryer a little does no good.