For the Hard drive, is there a way to add more, without disturbing the present one or do I need to completely replace it with a higher capacity one?
To add a second hard drive you will need to remove the optical drive and buy a caddy that fits into the optical drive space. Then you will be able to install a second hard drive without disturbing the main one.
We ordered 2 4GB Dell RAM Modules (SNPNWMX1C/4G) from the Dell Website. Despite your post, we were unable to get them working on a Latitude E6410 Laptop. We also did a BIOS Upgrade to A16, which didn't help. What du you suggest?