Unfortunately, there were some glitches when I was trying to do so. Do pay attention on the steps.
I was a happy man when I finally got the Samsung EVO 840 250GB SSD to replace my WD 320GB hard drive in my DELL latitude E4310. Please see the following steps:
1. Always backup any important files or the whole drive before attempting any of this. I do not hold any responsibilities for lost of data for attempting any of this below.
2. Pull out the A/C power adapter and remove the battery.
3. Overturn the laptop. There are two screws that securing the hard drive.
4. Remove the two screws. Pull the black plastic cover out. The existing hard drive is secured with a single screw with the plastic mount. Remove the screw on one end and another end is just a latch.
5. Finally replace with SSD. The screw the plastic cover back to the SSD on one end and another end secure the latch.
6. Now this is the step some of us at least me got wrong and spend the next few hours figuring out. Because the Samsung SSD is much thinner than the traditional hard drive. Upon pushing in the SSD into the slot, it does fit as tight as previously using hard disk. One need to be patient and careful by slowly pushing in the SSD into the slot. You will feel some 'tension' when you got into the correct position by slotting in the SSD. Otherwise you might have not connect the SSD's connector to the on board slot yet. You might need to repeat this step several times.
7. Once done, and power up the laptop. Press F2 to go into BIOS.
8. You will see your new SSD drive displayed under Primary hard disk section.
9. You are good to go. For me, I used the Samsung Migration software that comes with the SSD to clone my existing hard drive data.