If you have a older laptop then it's important to use in the expansion ram slot the same amount of ram as in the rest of the already filled slots, if you insert a bigger amount the motherboard will only read/use the same amount as the lowest ram value inserted.

For example:
If you have a 4 GB slot one and insert a 6 GB or more in slot two, your laptop will only use the total of 8 GB instead of the desired 10 GB of ram.

So only expand with the same amount of ram as there's already inside.

There is only two exceptions on this:

1. The above is for if the ram slots has the same color, you can for example put a 2 GB in the white slot and a 4 GB in the red slot and it will fully work. (I'm not sure if you laptop has multiple colored ram slots).

2. Newer laptops/pc from the last few year can hold different amounts of ram in the same group of slots.

There are... too many problems to count with this post. Either there's a lot missing from this story or something is very wrong here (or I'm just a hardware noob and am missing something).

• What do you mean you didn't "see" it? As in, on start menu > Computer > Properties, the "Installed Memory (RAM)" number is the same as it was before?
  
  
• The computer shouldn't even boot in most cases if you messed up a RAM installation. But if you seated it wrong or broke it, it should be showing less RAM, not the same amount.
  
  
• Most laptops aren't meant to be upgraded! The RAM can be soldered onto the motherboard, or very difficult to get at. Also I'm pretty sure all slots come filled! Did you just replace a 2GB stick with a 2GB stick from the old laptop? Because, no, you won't notice any change then!
  
  
• You seriously can't just grab parts from another computer and add them without knowing what you're doing. RAM can be incompatible, be a different version from the RAM you already have, or the computer could refuse to use certain increments of memory.
  
  
• The slowness could even be the processor (or software issues such as viruses). If you have 4GB of RAM, that's usually all you need for basic "work needs". So this could all be for nothing.
  
  

In short, I am extremely confused and concerned. Please take your computer to a specialist before you break it.

ram install is plug in and play its not hard,

your ram sticks might not work
your computer might not be compatible with your ram sticks


to install ram


>unscrew the panel
>put the ram into the slots
>put the panel back on

it is adviced to only perfom hardware mainternance/upgrades on your laptop if you know exactly what you are doing, if not you should find a specalist near you