If you really don't know what you are doing when it comes to mucking with your hardware on your computer, including buying and installing RAM, then take it someplace that will help you select the correct memory and install it for you. It's not really difficult to install memory, but I've seen so many people buy the wrong RAM and damage their systems trying to install it that it's mind boggling. Pay a little extra and get it done right if this is outside your realm of expertise and you aren't 100% clear and informed after doing some reading up on the subject.
jag