I've disassembled my 5051 AWXMi and found it similar to the 5050 disassembly link posted previously.
One thing I found was the ports on the front need to be slid back from where they poke through the case in order to remove the motherboard.
Once you've removed the screen and removed the screws under the hinge, at the back of the unit, underneath the unit and the keyboard and the DVDR there are only 2 screws holding the motherboard which have a large white arrow pointing at them.
My top tip to avoid loosing screws is to tape the ones you remove to a large piece of paper and write a description/sketch where it came from next to it.
For the ones underneath which are in a hole, I loosen the screw then put tape over the hole so that it can't fall out - then when you turn the unit over the screws are trapped in the right place for when you start to assemble it.
Hope this helps