There are 2 memory slots in the M70.
One is under a 2-screw panel on the bottom of the case, and one is under the keyboard.
Here are pictures.
First we put the laptop right back on its hinges:
Then we remove the bit of plastic by using a screwdriver on the gap on the right:
Then we unscrew the keyboard:
Then we flip the keyboard backwards gently:
Then we either remove or insert a RAM stick:
Then we do it in reverse.
That's pretty much it.
Finally, the M70 can take a single 2GB slot but no more than 2GB. It actually makes more sense to use the underneath-laptop memory slot than the keyboard route. It's DDR2 memory and looks like this: