Grab the SIMM at the ends, angle it a little toward the motherboard and pull it out. Repeat this with each module until they are all removed. When you lay them aside, make sure you keep the pairs together/in order if you removed two pairs.

Now it's time to install the new modules. Match the notch on the module with the key on the proper expansion slot. Then insert the memory module, at a 45-degree angle, into the expansion slot. Push the module downward into the socket, ensuring that it is fully inserted and properly seated. Rotate the module gently upward, allowing the latches on both sides of the expansion slot to click into place. The module can only be installed one way due to the notch in the module.

Now hook everything up again, but leave the cover off for now, so you can test it. After verifying all connections, turn the power on and watch the monitor carefully. If everything went well, you should see the initial BIOS screen and a counter which represents a memory test. Take a note of the final number of Kilobytes (KB). Don't be surprised if the number is actually a few thousand KB higher than expected. For example, if you installed two 64 Megabyte (MB) SIMMs for a total of 128MB, the number on the screen should be 131,072. That's because one MB is 1024 KB, and 128MB * 1024 = 131,072KB. If everything looks ok, you're all set. Put the cover back on and enjoy your faster PC.

Take a look at the modules. You will notice that they have two notches at the bottom end. If you take a closer look at the memory slots on the motherboard you'll see that there are two corresponding ridges in the slot. This will help you make sure that you insert them the right way.

Insert the first module vertically into the first DIMM slot (again, the order is important). Carefully apply even pressure straight down with your thumbs on the top of the memory module. The plastic clips normally pop into position all by themselves when you install the new module. But it sometimes helps to pull the plastic clips up and inward with your index fingers while pushing down on the top of the module until the DIMM snaps into the socket and the plastic clips snap into place. If you feel a little resistance, that's probably due to the tension of the metal contacts inside the memory slot. But if you feel a lot of resistance and it just doesn't snap into place, it might because of the notches, and you might have the memory modules inserted the wrong way. Repeat this with each module until they are all properly seated.
Now hook everything up again, but leave the cover off for now, so you can test it. After verifying all connections, turn the power on and watch the monitor carefully. If everything went well, you should see the initial BIOS screen and a counter which represents a memory test. Take a note of the final number of Kilobytes (KB). Don't be surprised if the number is actually a few thousand KB higher than expected. For example, if you installed one 256 Megabyte (MB) DIMM, the number on the screen should be 262,144. That's because one MB is 1024 KB, and 2568MB * 1024 = 262,144KB. If everything looks ok, you're all set. Put the cover back on and enjoy your faster PC.

But what if the upgrade didn't work? The most common problems after a memory upgrade are either a number of beeps or an incorrect display of installed memory. This is your BIOS telling you that it rejected the memory, most likely due to an incompatible memory type installed. Consult with your motherboard documentation and the vendor you purchased the memory from to find out what
type of memory is correct for your machine. Just to be safe, remove the memory modules again, make sure that you identified the DIMM slots correctly and started with the first one, and that you seated them correctly - then give it another try.