My rear passenger power window won't work. I searched the site and googled the problem but nothing fit my circumstances. All other windows and all door locks work. It got slower, more difficult, then stopped. WOuld you have a protocol as to what I should check?

 

I have had the problem with the same window. in my case it was a split wire inside the little wire holder thing inside the passenger door. this fixed mine for awhile but it has stopped working again haha and I haven't yet fixed it again. in your case with it getting slower and slower it may be the thing inside the door panel that helps the window run up and down. sorry I forgot what it is called at the moment because its rather late

 

window regulator is crapping out

 

Yup now I remember lol

 

I had to change two in my dodge stratus lol

 

Sound like the window regulator motor. Remove the doorpanel, which will give you access to that unit. You might be able to take it out and test it without the window attached to it. If it then works, than the weight of the window might be too much for the weakening motor. Easy replacement as a whole unit. (not sure if motor itself can be separately serviced or replaced).