I unsuccessfully replaced the glass on an HD2 today. After I got it back together the touch screen was unresponsive and I apparently damaged the LCD in the process. There are now several horizontal lines going across the display. Also, it didn't fit together really well after reassembly. I'll try again tomorrow. I would rate this procedure a very difficult.
Peel off the three layers of paper/adhesive from the center of the glass. Why is there three layers I do not know. There is just one layer of paper covering the adhesive on the edges. Peel and stick.
