Here is picture how to disassembly nokia E90
Open the sticker (as shown), you will see the screw , open the screw.
After the screw open, you can remove the front cover.
After front cover removed, you can remove front LCD by disconnected lcd connector.
Disconnected this connector.
Open this screw
By removing the two screw, you can separate between PDA Display and casis/plate.
Now you can disassembly/remove PDA Display.