Without knowing the exact mower you are working on, I will give you the most common answer. If the blades are belt driven you do not have to align them. They are positioned so that they will not contact each other and will overlap in their cut pattern.
most likely 2, look underneath
You will need to remove the cutting deck to get to the blades. Here you will find the drive belt, which you just slip off.
You have probably bent a blade. It is also possible that you just have dried mud caked under you deck. Most likely on the blades or spindles. Try washing the underside of your deck before you go replacing parts.
You will need to order a manual on the mower from the manufacturer (I assume Simplicity).
84 inch
5L74 gates
4L 63 inch
As long as they are close to the same year and model, yes. I have two decks side by side, one 38" and one 42", and all the brackets are the same. The belt will need to be changed for a longer one, though.
42" deck = 71" belt48" deck = 73.8" belt44" SNOWBLOWER uses V-Belt 131"
Grasses grow from the roots, which are able to avoid the blades of a mower. Study a lawn that has been mown a few days back, and notice that tips have been square cut by the mower blades, yet the grass has grown an inch or two taller (from the bottom).
just get new belts they stretch or buy a can of belt grip
The 42 inch deck belt is 104 X 1/2 inches.