http://www.mediafire.com/?2kyfww22mwn

this is the link to the N900 service manual. follow it very carefully. if you find that your job is done without disassembling the device further. don't go ahead and disassemble what is not needed. if you cannot take the device apart after removing the screws that are not broken, the steps that I have mentioned so far won't work. I'll find another solution if this one does not work.