Unfortunately, my friend Jim is a fine amateur mechanic. You’ll see why that’s unfortunate shortly. He drove to the stranded car, armed with most every Craftsman tool ever made.

Before the night was over he had checked everything. He was sweaty, frustrated and covered in grease.

As he sat in the car trying to start it one last time, he happened to look at the gas gauge. It was on empty. Maybe if he’d known a little less, he would have checked the gas gauge instead of attacking that poor Toyota with a wrench. Jim’s knowledge led him instead to the most complicated solutions.

Computers, like cars, often develop symptoms that lead a person to think that the problem is more serious than it is. I ought to know. On one occasion I came close to replacing a hard disk when the problem was really just the battery.

That battery protects a desktop computer’s memory of things such as the time of day or the status of hard disks and DVD drives. When the battery goes out, your computer becomes convinced that it no longer has a hard disk.

Today, we’ll talk about some of the frightening symptoms that can make a person believe they’re hearing the death rattle of a computer.

Let’s start with a familiar symptom - the mechanical clank. If you’ve been around computers for quite a while, you may know that a hard disk often makes such a sound as it fails. But other clanks are a lot less serious.

So if you hear one, check the computer’s fan. Blades can get out of whack and hit the wire screen that protects them. In most cases you can simply press out on the screen so that the blades no longer hit it. Problem fixed.

Another frightening moment comes when you turn your computer on and have no Internet connection. You brace yourself for the horrors of calling your Internet services tech support. Even when you run into a good tech support person, it’s still a long, drawn-out procedure.

But many connection problems can be fixed by simply powering down the modem -- whether it’s an old dial-up model, one for DSL or one for cable service. If it has a switch, click it off. If it doesn’t turn off, simply pull the power plug. Let it sit for a couple of minutes and turn it back on.

Most of the time this will re-establish the connection. That’s because it forces your modem to go through a process called "handshaking" with the modem on the other end. It simply means that the two modems get in sync and are able to talk again.

Since we are talking about easy fixes, I have to mention one that covers a variety of perceived problems. If something goes wrong, make sure that everything is plugged in and turned on.

One of my earliest high-tech memories at this newspaper, back before we had a sophisticated tech support group, was in the dial-up modem days. I was already writing the tech column, so it was natural that I got a call from an editorial writer who was having trouble connecting with a dial-up modem.

Sure enough, when I tried to connect, nothing happened. As I examined the computer and modem, I noticed that the wire from the modem to the telephone jack wasn’t plugged in.

As with the car with an empty gas tank, no amount of fixing would have helped, but checking the basics first saved a lot of trouble. I know this is really basic stuff for many of you. But the more you know about computers, the more likely you are to be tripped up by something simple. Just like my friend Jim, people with a good bit of knowledge have a human impulse to want to use it ... even when it isn’t necessary. (Bill Husted, NYT)