About 2 years ago I had a laminate floor installed in my living room. Recently when the floor is walked on it makes a cracking noise. The floor seems to be fine, no cracks, no spaces. What could be causing the noise?

Not an expert and do not know what temperature/humidity conditions the floor has been subjected to--but it sounds like a possibility that the floor has expanded and is trying to lift in some areas, creating some space under the floor. The noise could be the floor recontacting the subfloor as it is walked on. If this were the case, it would be tight to the walls-that is- no space btween the edge of the flooring and the wall and/or molding--maybe under the molding. Also, the chances increase that the above could be the problem if the temp/humidity conditions have been different in that room--from what they have been in previous year(s). This is just my best estimation based on some (not a lot of) knowledge in this area.