My screen wouldn't budge, nothing I tried couldn't get the plastic spudger started, even having the whole phone heated to loosen the adhesive. The way I worked it through was to *gently* push a small (2-3 cm) blade around the power button into the edge between the screen bezel and the steel frame. The hard steel blade started a small crevice, then I could work my way around with the plastic tool as described.

Hope that helps if your screen is as stuck as mine.