[erojohn]

I am a clean window person and do mine often. I wouldn’t pry on the bottom, it could damage the window or the frame. The silicone spay is a good thing once you get it open . I have used the following method successfully. I take a little soapy water and spray mixture on the outside of the window sill along the bottom from the outside of the house, through the screen. Spray bottle or squirt gun. The water soap mixture will eventually work its way inside the bottom sill. It may take a few applications and a few days persistence. It still may need two people on the inside to lift up. As with anything mechanical in a home it should be exercised occasionally to ensure ease of operation. Another example is the push on pull off water shut offs. They also should be exercised occasionally.