You need to remove the screws holding the screen into place, also the metal bracket that holds the hard drive, also the dvd drive, and the screws marked with a red line on the mainboard. More or less every screw you can see. The heat sink covering the processor should also be removed. When you get all the screws out - including everything you can find on the outside of the case the mainboard should start to lift away. You need to carefully disconnect the various sockets for sound etc which can be accessed as you start to lift the board. You should have removed the main and auxilliary connectors for the wireless (grey and black leads). The connector for the touchpad also needs to be removed by pulling up the clip (similar too the keyboard connector). When you have removed everything the mainboard comes away and you can remove the metal bracket from the side with the dc and usb ports. You can then access the underside of the mainboard for the solder connections.
Ian Enticott, February 2009