The Saturday after Thanksgiving, I couldn't help but shake my head as I read about the 17-year-old student who waited in the wee hours of the morning to grab that $229 laptop on sale. I was truly disappointed for the kid because he'll probably be disappointed by his purchase. The system he purchased undoubtedly was a loss leader -- an underpowered system meant only to draw people into the store.

Even if it has all the features, for that price it won't have the memory to operate optimally. And memory is key. So this year, instead of giving you a buying guide column, I'd like to help you not make the same mistake when buying your own computer.

In a typical computer, your programs and data are stored on your hard disk drive. Hard drives are fast, but not the fastest part of the computer. When you start a program or call up some information (a document, spreadsheet, music file, etc.), your computer's brain looks for that program or data on your disk drive and moves it to the main memory (a.k.a. RAM or system memory), which is much faster than the disk, and uses it from there. It's like pulling your cooking tools and ingredients out of your cabinets and fridge and putting them on your countertop where you can work with them.

In your kitchen, if you don't have enough counter space, you have to keep moving things around to make them accessible. It's the same way with your computer. If you don't have enough memory, the computer needs to move things out of memory back onto disk to make room for the specific part of the program or specific piece of the document that you're working on. Then, when you move to the next piece, it needs to switch out what's in your memory again.

Imagine having to pull out your kitchen mixer, using it for one ingredient, then putting it back into the cabinet for five minutes and taking it back out again, then going through this multiple times. It would take you a lot longer to complete your culinary creation. The juggling slows you down.

In computers, we call this paging -- where the computer moves the "page" back and forth between memory and disk to make room. Since it often takes longer to move the data than it does to work on it, it could increase the amount of time it takes to complete your task by two, three or even four times (where a 15-minute task takes an hour). It's also one of the contributors to the stuttering of your music and video files when you play them.

Using multiple programs or documents concurrently, or opening more windows uses more memory, that may increase the amount of paging, thereby slowing down a machine even more. Microsoft recommends that you have at least one gigabyte of system memory to run Windows Vista, the operating system that currently comes with most PCs. Most consultants (including me) recommend more. I wouldn't consider running a Windows Vista system with less than 2 GB of memory. Yet these bargain basement PCs usually come with  1/2 GB or less -- which is productivity suicide.

So while you can purchase a system with lots of great features for a small price, your satisfaction level will be poor, unless you immediately upgrade with more memory -- if the system even allows the upgrade.

So don't settle for too little memory when selecting your system. Doing so will affect every aspect of your computing experience -- even changing the meaning of "Black Friday."