While trying to put up shelves in our storage building I needed to cut some 1×4’s for the braces.  I have had this saw for 10 years and I don’t believe the blade has ever been changed.  My sister tried to cut some wood the other day and had a very hard time of it.  I purchased a new one and went about trying to change it.  I couldn’t figure out how to stop the blade from spinning while trying to loosen the bolt.  I found this video which was very helpful.  I hope it helps you as well.

Update:  Mine didn’t have a pin to push in.  Some directions tell you that there is a red button on the face of the saw and this will lock your blade.  Mine didn’t.  So I had to carefully hold the blade with a pair of pliers so I didn’t bend anything while I turned the screw.  It worked.