Before rushing off to a computer doctor to fix your sick machine, you should try to fix it yourself, say Joel Makower and Edward Murray, co-authors of "Everybody's Computer Fix-It Book," to be published this spring.

"You need only a few tools, a bit of patience and the desire to do it yourself," they say.

First, consult both the hardware and software manuals and use your own intuition, the authors suggest. Problems with computer equipment could range from not being plugged in to not being operated properly.

"Most times, in fact, a 'problem' isn't really a problem at all, but results from your misunderstanding how to do something, often the result of unreadable instruction manuals and salespeople who don't know any more about computers than is needed to get products out the door," Murray said.

To help a technician, come up with one or more likely diagnoses of your computer's problem. The more specific the better, the authors say.

Ask yourself: Does the problem occur only after the computer has been on for a while or is it consistent? Does the monitor display an error message when the problem occurs? Have you recently made any changes in your computer system, either software or hardware? Was the computer recently moved, dropped or did it suffer any other type of unusual event?

Another suggestion from authors Makower and Murray is to try calling the manufacturer or computer store. Many manufacturers and computer shops have technical service experts who can help solve problems via telephone. Several companies also have unadvertised toll-free "800" numbers. Check with "800" information to see if such a number exists.

Computer user groups and electronic bulletin boards are a good source of information. "If you float your problem out among your fellow computer users, you may not only find that you're not alone in your misery, but that some dedicated hacker spent the better part of three sleepless nights solving the problem," Makower said.

To find a good computer service shop, the authors first suggest asking your manufacturer or looking in the owner's manual for the nearest authorized service center for your equipment. Be sure, they suggest, that the machine will be serviced in the shop rather than shipped to a central repair facility.

Before settling on the authorized service shop, take a look at a few other places. Your computer dealer may have a shop or may be affiliated with one. An independent repair shop that specializes in servicing your type of equipment or repair might be another good choice. But, the authors caution, some shops may deal with only a few models, while others may specialize in specific types of repairs, such as disk drives or printers.

Moonlighting repair technicians also are recommended for fixing simple problems, such as aligning a disk drive or adjusting a printer. A local user group may know how to contact technicians who service members' machines at a special rate. After you choose a good repair shop, Makower and Murray suggest a few more tips to increase your chances of getting the best service.

As with doctors and car mechanics, you might get better service if you call ahead and make an appointment, they say. Get everything in writing, including details about what work was done, what parts were installed and what warranties apply to both parts and labor. Warranties for new replacement parts should be as long as for the original parts, typically 90 days. Rebuilt parts may have shorter warranties.

Charge all repairs, the authors say. "If you use plastic and later discover the repairs weren't done to your satisfaction, you'll have some leverage to get the problem corrected," Murray said.

And finally, Makower and Murray recommend four preventive maintenance chores to keep your computer in tip-top shape.

Once a week, dust off the entire system, including as much of the printer's inside as you can get to easily. Once a month, clean out the inside of the keyboard and examine the printer's belts for tightness.

Once every two months, clean the printer's print head, clean its insides thoroughly and clean the disk drive read/write heads. And once or twice a year, check disk drive alignment and clean the circuit boards.

"If you've got the smarts to get a computer up and running, particularly in light of the horrid state of computer instruction manuals, you certainly can clean your disk drives, install additional memory chips, configure a printer cable or do any of a dozen other tasks," Makower said. "And you won't even get your hands dirty."