How to upgrade RAM from 2GB to 4GB?

1. You can take the computer to a pc store and they can do it for you if and only if your laptop has any room for extra ram
2.Ram really won't have a major impact on how well minecraft and league of legends will run, it depends on the cpu and gpu

You'd have to check what type of RAM your computer takes, & what is its RAM limit & then you buy the RAM sticks.

Trade your 2GB RAM with 4GB Ram in store

Go to pc store and buy 4GB ram

Your RAM might be being used by other programs at the same time that you are gaming so right click in the system tray at the bottom of your screen, open task manager and see if there's anything running that you can stop.
Otherwise use the "Crucial Scanner" to find out how much and what type of RAM you have installed and what it can be upgraded to, or not as the case may be;
http://www.crucial.com/...ucial.com/
If it says that you can upgrade the RAM you do not have to buy it off Crucial, just get it wherever it is cheapest.
Regards, Bob.