windows in home built in 1978
There really is no need to take them out just to reglaze, but if you want to, you use a razer knife to cut along the paint line to break the bond along the window stop moulding that holds the window in. Then I tap a putty kinife in the crack to get the moulding to move away from the jamb.
Then use a flat bar between the putty knive and the jamb and gently start to pry it off.
Do the bottom on the sides first and work your way up. Most often you do not need to remove the top piece.
Tip the window out of the frame and disconnect the rope on the sides. Keep you hand on it so it does not just fly up into the pully.
Use a heat gun and a putty knife to get out any old putty. If it's loose it needs to come out.
Use glazing putty.
I like to get my hands wet and have a container of water to dip the putty knife in so the putty does not stick to my hand and the knife.
Take a blob out of the can and roll it between your hands to form about a 1/2" thick hot dog shaped tube. Use the putty knife to press it in place then hold it at an angle to smooth it out.
It's going to take some practices.
And just think while your doing it how much easyer it would be to never have to do it again if you installed replacement windows.
Plus all the money you would save in heating and cooling cost.