When you're trying to upgrade the amount of memory in your computer, it can be a hassle.  You have to know what types of memory your computer can handle, what speeds will work with it, how much you can have total, and how much you can have per slot.  This guide will help you determine what kind of memory you have, what you can upgrade to, how to find out what your computer maxes out at, and in general help you know more about computer memory.

For the purposes of this guide, RAM and memory can and will be used interchangeably.  RAM stands for Random Access Memory.

The first thing to do is to determine what kind of memory you have and how much of it there is.  This does involve opening up the computer case and removing the RAM modules.  If you don't feel comfortable doing this, STOP NOW and take your computer to a reputable computer shop.  They can take care of the upgrade and make sure that everything works how it's supposed to.  Still with me?  Good. 

Open up your computer and remove the RAM modules.  Most RAM has a sticker on it with the amount per stick and the speed.  Speed is usually listed as PC#### or as a speed in MHz.  For example the speed of PC5300 is 667MHz. 

Once you have determined the type of RAM you have and how much you have, you need to determine how much you can hold total and the fastest types you can handle.  If you are using a system purchased from a worldwide retailer (Dell, HP, etc.) it's usually best to go to their website and follow the support instructions to find out how much and what kind of RAM your system takes.  If you are using a computer that is custom built, you need to determine the model of your motherboard and go to the motherboard manufacturer's website  to determine the  information for your RAM.

After you have gathered all the information, it's time to choose what kind of memory you need.  If you are just going to add on and keep your current modules, it's best to buy a new module of the same speed.  While faster RAM modules will slow themselves down to match the others, there's a higher potential for problems down the road.  If you are going to completely replace all of your RAM modules, you can buy the fastest and largest amount your computer will support.

It's now time to determine how much RAM you want to upgrade to.  If you're running a 32-bit operating system (if you don't know the difference between 32 and 64 bit, odds are you're running 32 bit) the most memory it can recognize is 3.5 GB, even if your motherboard supports more than that.  There's no point buying what you can't use.  For most uses, 1GB of RAM will be enough.  If you are a gamer, multimedia enthusiast, or an overall power user, you would be better off with 2GB or more.

When determining what brand of RAM you want to purchase, remember to stick with the name brands, as they are higher quality, have better performance, and usually carry better warranties.  I usually recommend that people use Kingston, Crucial, Corsair, OCZ, Mushkin, Buffalo, or Patriot, in that order.  While they are a bit more expensive than other brands, the hassle they save you down the road is worth it.

Now that you've determined everything you need to know, it's time to actually buy it.  I won't tell you where to get it, but if you can, try to buy wholesale.  You get the same parts for dirt cheap prices.

Once you have your RAM, open up the package, put it in the slots on your motherboard, close it up, and boot up the machine.  As it's booting up, enter the BIOS (depending on your computer, this could be called setup, CMOS, etc.  Usually you hit one of the function keys just as the computer is booting up.)  If the BIOS shows the correct amount of RAM, then you're good.  Most BIOSs will display the amount in MB instead of GB.  Remember that 1024 MB = 1GB, 2048 MB = 2GB, and 4096 = 4GB.  If the number is only off by a few megabytes, don't fret.  Sometimes machines will reserve a few megabytes of memory for their own uses.  This is normal and is nothing to worry about.

Congratulations, you've upgraded your computer memory and should now be noticing the improvements.

I have been working in computer tech support and repairs for 2 years now and have the CompTIA A+ certification.  If you have any questions regarding the above information, or anything else about your computer, feel free to send me an email, and I'll do what I can to help you out.