Q. What is the difference between a Celeron and a Pentium CPU?

A. CPUs are like quarterbacks in the National Football League. The Celeron is the average $3 million-a-year NFL player. With the correct team, you can build a winner around this CPU. Let's say you load up the memory (offensive line), put in a fast SCSI hard drive (running back), a brand-new video card (Pro Bowl receiver)--you will have a good machine. It is no contender, but can hold its head up around the league.

The Pentium III/600 is the $12 million quarterback. If you put poor components around him, he will perform well, but don't look for any postseason appearances. If you load him with some hogs upfront (128 megabytes of RAM), a fleet-footed halfback (Ultra-2/LVD SCSI hard drive), and a sure-handed receiver (Creative TNT2 Ultra), you are sure to pay a visit to the Super Bowl.

You will find Celerons configured for average-duty home users; the Pentium III/600 will normally be found in corporate environments or in the machines of determined gamemeisters. Remember that very few teams can afford the high-priced first-round draft choice--most do very well with a regular guy throwing the pigskin.

What are the differences among these four cards from Creative Labs: the Banshee, 3D Blaster Savage, TNT2 and TNT2 Ultra?

When a company such as Creative Labs designs a video card, it tries to answer some basic marketing questions: the final resale price of the board, memory interface and amount of memory, among many other considerations. As a result, video-card vendors make cards for different market segments.

The Creative Banshee came out last year and is considered old technology (!). It is the slowest of the group and was designed to sell for around $100, along with the Creative 3D Blaster Savage. Both of these cards are classified as handling pixels in a single pipeline. This means that when they do 3D rendering, they process one 3D pixel at a time.

The next two (the TNT2 AGP and the TNT2 Ultra) are newer boards and can handle two pixels at a time. These are priced in the range of $180 and are considered to be among the latest and greatest of today's technology.

For the general consumer, this is useless hairsplitting. There are very few applications in the business world that take advantage of 3D effects. But if you put your gameplaying hat on, you are in a different world. A better card can give you more frames per second--which yields more fun.

I have heard about a new type of virus called "hackertool." What do you know about this?

It all started with a guy named Dan Farmer. Around 1995, he took it upon himself to design a tool that would let system administrators test to see if their networks were safe from attack by hackers. It was called Security Administrators Tool for Analyzing Networks, or the clever acronym SATAN.

In a similar vein, a group of modem-savvy hackers decided to test one of Microsoft's server suite of products--Microsoft Back Office. They call themselves the Cult of the Dead Cow and have received a ton of publicity. Their most recent offering is called Back Orifice 2000 and is designed to show weaknesses in the Microsoft product.

It is increasingly difficult to define exactly what a virus is these days. In addition to good old macro viruses, we see more and more code such as Trojan horses and these network-testing programs. Most folks probably would not classify Back Orifice as a virus; some would call it a Trojan horse. Call it what you want, it can cause trouble.

Fortunately for most of us, we will never encounter any "hackertools" like these.

John Gilroy of Item Inc. is heard on WAMU-FM radio's "The Computer Guys" at 1 p.m. on the first Tuesday of the month. Send your questions to him in care of The Washington Post, 1150 15th St. NW, Washington, D.C. 20071-5302 or via e-mail at jgilroy@iteminc.com.