What type of yeast are you using? How long since you pitched it? What was the temperature of the wort when you pitched it? What is the ambient temperature of the room where your fermentor is?
DO you have a gravity decrease? Honestly, the amount of krausen present and/or airlock bubbling or lack of it, are irrevelant if you have fermentation.....
And the only way you truly know if you have fermentation is with a gravity reading.
i brewed a witbier that had no krausen at all during fermentation, it's been in the bottle for 2 weeks and a sample tasted great, should be a really good beer in a couple of weeks.