Your hard drive (or hard disk) can be thought of as the filing cabinet of your computer.  Even when your computer is turned off, the hard drive is still storing all of your files (such as your email or a recipe you save with MS Word), your programs (such as MS Word itself) and everything else the computer needs to be useful for you.

When you turn your computer on, some of the data that is on the hard drive is pulled into memory – it is what your computer is “thinking” about.  As you need to the computer to think about more things, those things are brought into memory.

For example, if you decide to surf the web, your web browser (such as Internet Explorer) is pulled into memory so the computer can “think” about it.  It is also left on the hard drive, so it is really in both places.

If you ask your computer to think about too much, sometimes the computer has to, in essence, take notes on what it is thinking about to make room for the new stuff.  Hey, we all have to do that, right?  The computer does that by putting some of what is in its memory back onto the hard drive using what is called “virtual memory.”   This allows the computer to work with those notes faster than it would if it had not noted the data at all, but it still slows things down.  You can often tell if your computer is doing this a lot of you hear the hard drive “grinding” as you move from program to program. Memory is completely released when you shut your computer down.

The most common item to upgrade when you want to increase the speed of your computer is its memory.  Most people do not have to increase the size of their hard drive – modern ones hold massive amounts of data.  It is not uncommon to have 300 or 500 or more Gigabytes of hard drive space on a new computer, where 1 or 2 Gigabytes of memory is typical  on a modern computer (if you do not know what a Gigabyte is, just suffice it to say 1 or 2 units is a lot smaller than 300 to 500!)

If the above is confusing to you, know this: for most people, the best way to extend the life of an aging computer is to add more memory.