Plumber, electrician... digitician?

Paul Gosselin is battling the mother of all viruses.

Furiously clicking his way through the operating system on his customer's personal computer, he squashes cookies, pop-up ad files, and viruses with abandon. Then he encounters the big one. Gosselin's antivirus program triggers a counterattack by the virus that shuts the computer down. The "blue screen of death" flashes up. He tries again and again, but the virus is winning. In a final, stealth attempt, he hunts down the virus file, renames it, and slays the opponent.

The day's spoils: 1,136 pieces of spyware and 42 viruses. "It had Ebola," Gosselin tells Meredith Judge about her family computer. "One of the worst ones I've seen."

Another day's work for Gosselin, an employee of Geek Housecalls and one man in the burgeoning army of overqualified, unemployed, or free-spirited computer technicians being deployed to front porches around the country. Gosselin is a Harvard MBA-turned-computer nerd laid off from his prior full-time job. This new breed of tradesman can solve the technical problems of increasingly wired homes with PCs, laptops, personal digital assistants, BlackBerrys, DVD players, cable, faxes, printers, cellphones, and the wireless web.

For many tech-savvy households, the services of these itinerant professionals have become indispensable in an era when expectations of what technology can do are rising and the machinery has become too complex for the average person to manage. They can remove a carpet of dog hair from any hard drive vent, one of numerous computer-related tasks awaiting them in the American home. They restore old computers, set up new ones, network multiple home computers, install and smooth out programs, organize tangles of cables, debug, kill viruses, train, even customize computers to fit the quirks of any family configuration.

"While Dell might help me with my computer, and the cable company might help me with my cable modem, there's no one who does it all," said Paul Osterman, a professor who studies work in the Sloan School of Management at the Massachusetts Institute of Technology. "It may be the beginning of a profession. It's being driven not by your computer, but your home network in the house and the increasing complexity -- it's creating a need for this."

As early as the 1990s, a few pioneers made house calls. But the business has surged as word travels among neighbors, friends, co-workers, and professional networks. A conservative estimate of at-home service puts it at a $7 billion market -- and growing. Prices for home visits range from $30 to $125 an hour. The Judge family paid nearly $300 to fix an $800 computer.

Computer technicians who make house calls may be one-man shops or employees of regional companies like Geek Housecalls, which has customers in Massachusetts, New Hampshire, and Rhode Island. There are also national operators aspiring for brand recognition like Jiffy Lube or Merry Maids. The trademark for Geek Squad, acquired in 2002 by Best Buy, is the black-and-white Volkswagen Beetles the company's technicians drive to house calls.

Ken Smith has a name for them: "digiticians." That's what he named the firm, The Digiticians, he founded with Anne Marie Biernacki in Waltham. The Digiticians' sophisticated technology has taken the house calls out of at-home service. The company can, with a client's permission, take control of their home PC.

He compares the technology to NASA guiding rovers on Mars. What's visible to customers is a cursor moving around on the screen. Digiticians' technology can be used to train clients, fix software glitches, run virus programs, and make repairs.

The company has customers in 18 states and four countries, demonstrating the viability of a national or international customer base, Smith said. Some things can't be done remotely, such as fixing a bad motherboard. "We can do about 80 percent of the problems that come our way," he said.

As both the profession and technology itself matures, it will become clear whether this will be a national business or a local one. But, those who are good at what they do might be the kind of iconoclastic, independent people who do not cotton to working for a corporate conglomerate.

"The name of my company is, 'I Hate Computers,' " said Paul Day, who began making residential house calls a year and a half ago. Day, whose wife works full time, is a part-time digitician, freeing him to be home when his two daughters return from grade school. The job also allows him to pursue his avocation as a stand-up comic, with Monday night bookings at Jimmy Tingle's Off Broadway in Somerville and a radio program on WMFO (91.5 FM). Day has worked with computers for 12 years; past employers include Rykodisc and eYak.

With some 70 residential clients around Boston, he knows why business is growing: Home PCs are personal. Technicians are the modern-day plumber or electrician. "Even though people don't understand their computers, they don't really want to give them to somebody, " he said. His customers need reassurance their computers, with their mysterious inner workings, are fine. "I bill myself as a computer therapist," Day said.

A good computer-side manner is critical. "There are all different kinds of people you're dealing with. Some don't understand much about computers. You have to talk at their level but you don't want to insult them. You don't want to use jargon. You have to understand what they need and communicate to them what you're doing," he said.

Smith said the people he employs must possess composure. Home computer problems, badly handled, could mean the loss of important personal information or the dissolution of a marriage. "You're walking into a firestorm," he said. "Something has broken, and there are potential catastrophic ramifications. If you freak out, you're going to blow up the situation -- it's like a doctor coming into an operating room and saying, 'Oh my God!' "

David Ledoux -- professional name, "Dr. Dave" -- has taken customer service to a higher level. Each customer, he said, has "personality. You've got Tom Jones, with three kids, and you have to learn that his oldest kid likes to do file-sharing and the youngest one needs to have most of the Internet shielded from the bad stuff because she's 9."

Clients tend to be upscale or own home-based businesses in leafy suburbs like Newton, Sudbury, and Wellesley. Dr. Dave, who employs four other technicians, charges $125 an hour, though less for low-tech aspects of a job. On a recent Thursday night house call, he delivered a sleek, new Dell laptop weighing just 2 pounds to Maxine Minkoff, an educational consultant. A tiny sticker with the Dr. Dave logo is affixed to her new keyboard.

Minkoff's relationship with Dr. Dave began with a referral from a neighbor. She hired him for a routine visit to fix her computers, which she shares with a daughter living at home who attends graduate school. To select her laptop, he did a "needs analysis" to determine the best one for her, something so light she can take it with her out of town to type notes during interviews and meetings.

During this visit, Dr. Dave sets up the laptop, transfers her e-mails and data to it and synchs the entire system with her Palm Pilot and pen drive, a tiny hard drive that plugs into the laptop. He is also setting up a wireless connection so she can work on the backyard deck or at Starbucks during consulting gigs. He crawls under her desk to find a cable; she has hired him to return in the future for the sole purpose of reorganizing the proliferation of cables.

As users go, Minkoff is sophisticated and had always bought and set up her computers. She increasingly turns to Dr. Dave, because he is attuned to her unique needs.

"Dave is very good at that," she said, and "that makes a difference."

Kimberly Blanton can be reached at blanton@globe.com.