NEW YORK (CNN/Money) - Brian Peterson calls himself "computer illiterate," even though he uses his home desktop to run his small trucking company. Two days ago, he got the worm.

"I was trying to check my e-mail Monday afternoon and I couldn't get into my computer," said Peterson, who lives in Maple Grove, Minn. "The computer would shut down, turn on, shut down and turn on. It didn't do any damage, but it was a terrible nuisance and I was frustrated."

So Peterson decided to take action. "I called the 'Geek Squad.' They said, 'Oh, yeah, you've got it.' It took them two minutes to fix it, but it cost me $250 for the house call."

Best Buy Corp.'s (BBY: Research, Estimates) Geek Squad tech-help unit has been inundated with similar calls from frantic home users and small businesses this week after the Blaster Worm -- the latest Internet-borne computer pest to hit cyberspace -- attacked their personal computers.

Robert Stephens, founder of Geek Squad and vice president of the new business development division at electronics retailer Best Buy, estimates that thousands of home users will take a hit from the new Internet worm.

"The phones are ringing off the hook," said Stephens. "We received hundreds of calls Monday when the worm struck, and they're still coming. This worm is like a fast-moving thunderstorm. It comes in fast and then it dies out quickly. We expect yesterday [Tuesday] and today [Wednesday] to be the peak."

Dubbed "LoveSAN" or "MSBlaster," the worm exploits a flaw in Microsoft's Windows operating systems. Once the machine is infected, computers are forced to reboot repeatedly.

That's what happened to Matt Camassa's home computer Monday night.

"I logged on around 10:00 at night and the computer shut down and then rebooted itself five times," said Camassa, a Manhattan-based consultant.

Camassa figured out that his computer was "Blastered" after he spoke to a friend about it.

Internet security professionals say home computer users typically are easy targets of viruses and worms because many either don't have sufficient anti-virus protection already set up or they don't have the same level of technical know-how that businesses already have on board through in-house tech-support units.

"Home users are hit pretty hard because they have a bigger window of vulnerability," said Brian Czarny, marketing director with MessageLabs, a provider of e-mail security software.

And the costs can be staggering.

According to Best Buy's Stephens, consumers and businesses suffered billions of dollars in lost data, lost time and business, and repair costs in the aftermath of the nefarious Code Red virus in 2001.

But home users can cushion the blow a little by taking a few basic precautions, Stephens said.

"If there is one silver lining, it's that these situations help raise awareness about the usefulness of a safety belt," said Stephens. "Think of a computer with an Internet connection like an open door. Once in a while, check the lock, turn the key and see that it works."

In other words, he suggests users install a "firewall," or software that offers computers maximum protection against viruses. Additionally, users should check for updates of anti-virus software that many companies offer for free downloading or a "patch" that can protect computers against a known virus.

Katrina Lobbia, a Web designer with Hamptons Online, did just that. "I have a firewall and I also downloaded the patch from Microsoft to guard against this worm." But Lobbia admits the Code Red virus did get her. "I'm more careful now."

In most cases, it's not necessary for computer owners to dish out big bucks for basic antivirus protection, since it can be downloaded for free.

"But you can buy anti-virus software for about $20," said MessageLabs' Czarny. "Put a firewall in place to protect your computer if you have a cable modem for your Internet connection. It costs between $40 to $100."

In the meantime, the Geek Squad is awaiting a possible next wave of attacks this Saturday, when the computers infected with the worm are supposed to attack a Microsoft site dedicated to fixing it.

"Unless the worm has already been removed from the computer, it could update itself and send out a huge package of garbage on the Internet on the 16th," said Stephens. "The second time around it could cause massive damage."