Microprocessor
If you're running business or campus applications and surfing the Web, a 2-gigahertz Intel Pentium 4 chip (or the comparable AMD 2000+) will be fine. If you're manipulating photos or playing high-end games, move up to a 2.6 gigahertz Pentium 4 or AMD 2600+. This type of computing requires more power.

As for Apple, the low-end eMac uses a Motorola G4 processor at 700 megahertz. Apple claims that because of the way the chip works, the 700-megahertz unit is about equal to a PC chip running twice as fast. An eMac should handle campus apps and surfing. If you need something faster, Apple offers the Power Macs, which have two G4 microprocessors that work in concert to boost performance. Each of the chips runs as fast as 1.25 gigahertz. You will probably find the low-end Power Mac sufficient. It has two processors that run at 867 megahertz.

Video cards
Video circuitry often shares memory with the main system, so you don't necessarily need a separate video card with its own memory. Business or campus applications and surfing won't stress your machines graphics capabilities and don't require a separate card. If you're a hard-core gamer or working with digital video or photography, equip your computer with a separate video card. It should have at least 64 megabytes of memory known as DDR SDRAM. Choose a card with 128 megabytes and a digital output if you're buying a digital flat-panel monitor.

Hard Drive
Most low-end computers have 40 gigabyte drives. That's more than enough for most. Don't put an extra dime into this area.

Memory
You need at least 256 megabytes of memory, called RAM, to run the latest operating systems such as Windows XP or Mac OS X. If you want to be on the super-safe side, get 512MB. Manufacturers sometimes offer a free upgrade to 512MB as an inducement to buy. While you don't need that much straight out of the box, you might in the future.

Operating System
You're running out of options here and don't have much of a choice. You'll get what they give you, which is Windows XP or OS X for the Mac. Both are stable, competent operating systems. If you do have a choice between Windows XP versions, choose XP Professional - here's why...

Monitor
Here's a good place to invest. You'll want a minimum of a 17-inch CRT (cathode ray tube) monitor or a 15-inch flat-panel display. Prices continue to plummet, so 19-inch CRTs and 17-inch flat panels are cheaper than ever. But keep in mind that a 19" CRT may not be the best choice for a dorm room, space is limited. The vast screen real estate they provide is worth the investment. If you pick a flat-panel monitor, consider choosing one with a digital connector, often called a DVI (digital video interface) port. Though monitors with digital connectors generally cost more than those with analog connectors, they produce a better picture.

CD or DVD Burner
The capability to make CDs or DVDs is handy, whether you're backing up data or making music. CD rewriters (CD-RWs) are inexpensive and well-suited for music; DVD burners can put much more data on a disc. That could be important for backups or home movies. CD-RWs run less than $100; DVD burners run triple that, or more. But they can make CDs in addition to DVDs.

Warranty
Computers are relatively easy to fix because you swap broken parts with new ones. If you're handy, get a one-year warranty. Otherwise, look for a system that offers a three-year warranty. Most companies offer a one-year warranty, but they often sell extended service contracts, such as the Apple's AppleCare, to extend it.