First -- it is one heavy dude! It is manageable for one to take out-- but be smart-- get a six pack and some friends.
Remove the wiper inspection covers in the header. You will see the hinges. Crank out window-- which maybe a challenge as you mention the crank isn't cranking. Try and have one of those buddies push gently at the bottom of the window while you try cranking it out. You need to remove the crank out mechanism from the window frame BEFORE you loosen and remove the windshield frame from the header.
The bad news here is --- the screws are slots, the thread is fine, and if your vehicle has had any water near it over the years, the screws are rusted tight.
What I am politely saying is -- this is a major project and I am not even talking about trying to line it all back up to re-install. (Henry had a secret on doing it, and I think he took it to the grave.)
It is one of the toughest things to do. Others may have secrets to share, but I haven't heard of them. I spent over 60 hours trying to get my 1936 pickup frame back in --- still isn't in. And I am out about 2 cases of beer.
I would focus my attention to getting the window to crank out. And then see if you want to replace anything else.
HINT: It is the wrong time of year to think about removing a windshield, unless you have a great pair of googles you want to be using for a while.
Not trying to be totally negative here -- just letting you know what you maybe in for.
Try Drake for windshield gasket.