First Time Homebrewer with Fermentation Question

I'm a newbie homebrewer and I just made my first batch this weekend. I cleaned/sanitized my equipment, followed the recipe, pitched the yeast and set my fermenter aside to start working @ midnight Sun. I checked it 6:30 Monday morning and it was already very active - I had foam coming out of the airlock. But when I returned home from work and checked it all activity had stopped - no bubbles - nothing! And there it sits today as well. From what I've read I should have active fermentation for 3-4 days before it subsides. So what's the scoop? How do I tell if it's still ok, or if I have a bad batch? Help!

What type of beer are you brewing?
What type of yeast?
What is the temperature?
What's the OG?

Answer those first and a more educated response will surely come.

My very uneducated response though is that you are fine. You might have it at a higher than desirable temp and/or could be a result of the style. My hefes ferment quick and hard like that.

You haven't ruined the batch. The flavors might not be ideal for the style you are making but you actually might prefer the taste. I'd give it another couple of days of fermentation and then take a hydrometer reading. That will help you more accurately determine whether to move to secondary, keg or bottle (depending on what next step you are planning).

One possibility is your fermentation temp was way too high.
You can ferment out in 2 days if you pitch into 80 F wort and keep it there.

The fastest fermentation I've had was 34 hours, the longest about 8 months. 3-4 days is typical and when the airlock activity stops is when you take a hydrometer reading.

Another thing to check for is a clogged airlock and your seals.

If the airlock is closed off your brew may be outgassing elsewhere; airlock gasket, lid gasket.

Remove and clean out your airlock and see what happens from there.

Ya'll, thanks for your help.

Poguemahone - to answer your questions:

What type of beer are you brewing?
a pale ale recipe that I got off the internet.

What type of yeast?
Munton's dry ale yeast

What is the temperature?
Don't know exactly - the fermenter is in my pantry/laundry room which is between the kitchen and garage. I'm sure it's warmer in there than the rest of the house!

What's the OG?
Don't have a clue as I don't have a hydrometer. I was told at the local homebrew store that I didn't have to have one. What is the OG/FG going to tell me?

The og/fg will tell you if fermentation is finished or not.

Temperature is important- I'd recommend a stick-on thermometer that they sell at LHBS. You want this to be 70 degrees or so- if it's warmer than the rest of your house (whatever temperature that is), it's probably way too warm for it. Fermentation is probably finished due to the too-high temperature. You might have some off-flavors if the fermentation temperature was high.