Shopping for a computer begins with learning to read technobabble, the language of computer advertising.
Here's a plain-English translation of some important features:
--"64MB 100 MHz SDRAM" means the computer can store 64 million bytes of information without using the hard disk or another permanent storage medium. A byte consists of eight binary digits, or "bits," and can store enough information to identify one English character. SDRAM stands for Synchronous Dynamic Random Access Memory. Unless you're interested in a history of computer chips, the only thing you need to understand is that the more RAM, the better.
--"20X min./48X max. CD-ROM" means the Compact Disc Read-Only Memory drive will transfer data at a minimum of 20 times the speed of the early CD-ROM drives and at a maximum of 48 times. That makes sense only if you know that the early computer CD-ROM drives transferred data at about 150,000 bytes per second. Remember that if the advertisement says "DVD ROM," it means Digital Versatile Discs also can be used.
While we're on the subject of bytes and bits, don't always assume that MB and KB stand for megabyte and kilobyte. According to convention, if the letter B is lowercase, it means megabit or kilobit. But this rule is not always followed, so be sure to check.
Moreover, the common meaning of the prefixes mega- and kilo- are million and thousand, but the actual number of bytes or bits in question is slightly more. Because computers use the binary number system, a megabyte in our decimal system is 1,048,576 bytes. With some games now requiring 500MB and up, more is always better.
--"USB" is the Universal Serial Bus, which is a way of hooking peripherals to the computer. Be careful when buying a new machine if you intend to use printers and other widgets you already own that need parallel and old-fashioned serial ports. Some of the new machines don't have them. Of course you can always buy peripheral cards to add parallel and serial ports to USB-only machines.
--"PCI" stands for Peripheral Component Interconnect. It's a standard for the expansion slots where you plug in peripheral cards to your computer.
--"CPU" is a Central Processing Unit. It is the part of a computer that actually computes. You'll usually see a number next to it. "733 MHz" means the CPU processes data at the rate of 733 million cycles per second. Faster is better, but so many other factors affect a computer's overall performance that it's not the absolute determinant.
--"Motherboard" is that squarish, greenish thing into which all the computer's components are stuck. It allows the components to communicate with each other.
--"32KB L1 Cache, 256KB L2" describe different cache systems. A "cache" is a small memory system that stores recently used instructions and sits between the processor and the slower main memory banks. An L1 cache is on the chip itself. An L2 cache, which is on the motherboard, talks to the L1. Because caches speed processing, bigger is better.
--"AGP" stands for Accelerated Graphics Port. It is a slot on the motherboard that handles graphics faster than a video-adapter card in a PCI slot would.
Another thing to keep in mind when you are thinking about buying a computer is that monitors are advertised in terms of inches, but that number doesn't describe the viewable area.
A 15-inch monitor, for example, has 13.8 inches of viewable area. Also remember that modems may be rated at 56 Kbps (kilobits per second), but they will most often perform at less than that speed because of telephone-line quality.
Interested in more technical definitions? Here's one online tech encyclopedia with about 20,000 definitions and plenty of good diagrams: http://www.techweb.com/encyclopedia/