Power down the system and remove the AC Adapter.
You have already opened your case to look at the RAM.
Put the system on its side to work on it. On either side of each RAM module are two clips, just shove them out and pull out the RAM modules. Insert the new modules in and push down the modules apply a bit of force and make sure they are in tight you will hear them clip in.
That's it, its the easiest part to replace in a laptop or desktop.
Install the RAM before 7 64 bit.