For the technically illiterate, here's a brief overview of what's inside of a computer. My goal here is to give you just enough information to be dangerous, akin to a mechanic telling you what the parts of your car are, and to give you some useful jargon to throw at your computer tech and make the poor pimple-faced teenager even more confused than he already is.
First off, a computer is designed to [b]store[/b], [/b]process[/b], and [b]display[/b] stuff. In order to do that, it has to be [b]kept cool[/b] and [b]provided with power[/b]. If you divide the computer into those parts, suddenly the computer starts making a lot more sense. But don't let that deter you from jargoning up that PC tech!
KEEPING IT COOL
Those fans you hear whirring? Those are to keep the system cool. Some of those fans are to keep the parts that provide power cool, too. These are called the "fans".
JARGON ALERT: Often, if you hear a very loud grinding or whining noise from your computer, you can say it sounds like "a fan threw a bearing", or perhaps "the bushings are worn out", or even "the fan might be rubbing on the shroud". These useful terms may get your PC tech to happily respond with his own anecdotes regarding the time his high-end gaming PC "blew a fan on the water-cooling rig and I couldn't play games for DAYS". Just nod, pretend you empathize, and let him keep working.
PROVIDE IT WITH POWER
You've got an external power brick for your notebook that tends to get really warm, or maybe you have a desktop computer with some funky fan-grille thing in the back with a power plug in it. There's a big power plug that connects to the wall somewhere on that thing, and this part of your computer gets REALLY WARM. This is the most likely place for SPARKS and SMOKE, and if your computer simply won't turn on at all, make noises, beep, boop, light up, or hum, this is probably the part that is broken.
JARGON ALERT: "Looks like the PSU let the magic smoke out" or "my power brick is no longer providing regulated voltage" will get that tech on your side and keep him honest, thinking you actually know something about your PC.
Inside your computer, you probably have a DVD drive and a hard drive. These two parts allow you to store information. The DVD drive is that cup-holder on the desktop box, or perhaps the little slot you slide discs into on your macbook. The hard drive, on the other hand, is where you store your stuff forever.
Unfortunately, nothing lasts forever, and since both of these parts have a substantial amount of parts whizzing past each other several thousand times a minute, they tend to get out of alignment and die horrible, crunchy, gravelly deaths. If you hear a grinding noise, or see a light flashing all the time while your computer spins an icon on the screen forever, your hard drive might be dead.
JARGON ALERT: "The drive has bad sectors" or "Could it be a head crash?" are great terms for keeping that keyboard monkey in check while he's working on your machine. Calling your DVD or CD drive a "cup holder" is a great in-joke, and will convince that PC repairman that you are part of that tiny in-crowd who really know what is going on. Or, at least, that you finally got your hands on a chain email from 1998.
Now, this is where it gets confusing. Most of us are used to referring to the big beige box as the "CPU". Well, it turns out the CPU ("Central Processing Unit") is really only one tiny part of that beige box, but it's where most of the heavy lifting happens. This part gets REALLY HOT, and is the primary reason you have to cool your laptop down.
The "CPU" plugs into a "motherboard", that basically is a glorified housekeeper. The motherboard has lots of little ancillary processing units that take care of all the crap your CPU is too busy to do.
JARGON ALERT: If you get a particularly old PC tech working on your system, try throwing out "Heh, heh, I wonder if the Pentium floating-point bug maybe came back" or perhaps "Maybe we could just solder a pin on this to turn it into a 486 DX2?" to get a laugh and convince him you're one of the gang.
Your computer has some sort of screen that keeps you glued, watching, and probably is supposed to make sounds. If either of these stop working, you can blame your "monitor", your "GPU" (only if you play games and the games stop working), or your "sound card".
JARGON ALERT: "Could my GPU be sharing an interrupt with another card?" will get that PC tech haring off down red-herring road faster than you can say "Nip!", "Pang!", or "Nu-Wom!".
I hope this primer has been helpful. Enjoy your new computer.