Choose the RAM memory is a puzzle? Not at all!
In proceeding by elimination, we come to find THE correct memory for your computer. First go on a shop with some criteria to filter out the products.
Then, in our machine, we have a motherboard with AM3 socket (to mount an Athlon II). So we need DDR3 memory. In case of doubt, a quick Internet search will give you the type of memory to associate with your processor. 
The motherboard is the heart of a computer. On it we will connect all the other components: processor, memory, power supply, hard drive... Everything is connected to the motherboard.
So its choice is crucial for your computer.
This article is a continuation of the series to choose your hardware easily. For more information, there are many good comparative. My goal is to make the most neophytes realize that select all its components is very interesting.
For the processor, the first thing is to define the use of the computer, it will determine whether to emphasize the frequency or the number of cores.
Actually choosing a hard drive is an easy part, since almost everyone plebiscite the SATA hard drives from Western Digital, in particular Caviar Blue.
If for the old interface (IDE) Seagate drives were quieter, they are not so good in SATA. Hitachi, IBM and especially Samsung are good alternatives.
Power supply unit (PSU) is often overlooked in the selection of components of a computer. Nevertheless it's an important part, even essential: without a good stability of the current supplied, you could have the better processor in the world, your computer will crash constantly.
