ID stolen? Call a privacy gumshoe.

Your phone bill says you've made long expensive calls to remote island nations you've never heard of. Your computer floods screen after screen with ads and runs as if someone poured molasses into it. After faithfully paying bills on time for years, you apply for a loan and are told, "Sorry, not with your bad credit."

If these scenarios sound familiar, it's a good possibility that your computer or your personal financial information has become the personal playground of a computer hacker or identity thief. Each year 10 million Americans have their identities - their names and personal information - stolen. They lose an average of $500 and spend about 30 hours trying to clean up the mess, according to a 2003 survey by the Federal Trade Commission.

In this discouraging, even frightening situation, privacy gumshoes offer a ray of hope. More adept with gigabytes than guns, these 21st-century Sam Spades can make the problems go away - for a price.

At the top end are companies such as Gavin de Becker & Associates, a California consulting firm that among other things advises celebrities and other high-risk individuals on how to "hide your identity from people who'd like to steal it," says Beth Givens, director of the nonprofit Privacy Rights Clearinghouse in San Diego.

The fee: Don't ask. (Mr. de Becker is out of the country and unavailable to speak, and no one else at the company is permitted to talk about its work, a spokeswoman says by phone.)

Some private investigators will track down records and straighten out identity theft too, Ms. Givens says, but they can be another potentially pricey option. Or you can do it on your own, if you have the time and energy, she adds. "Protecting your privacy is not something you can do in an afternoon." Her website, www.privacyrights.org, offers 40 fact sheets on how to do it.

But just as some people can't bear to face tax season alone, they want more than a list of tips.

Last year, Allstate Corp. began offering identity-theft insurance in Texas and a few other states as a $30 rider on its homeowner and renter policies. The spadework is contracted out to Kroll Inc., a risk-consulting company. "We take a lot of the work of identity restoration off the shoulders of victims," says Troy Allen, vice president for fraud solutions at Kroll. "It's very time-consuming and difficult and frustrating." The Allstate plan includes filing paperwork for the victim, such as notifying credit-reporting agencies, credit-card companies, and the Social Security Administration. Kroll will also help victims understand their legal rights and work with police and collection agencies to sort out claims - basically, everything except those tasks that victims must do themselves, such as report the crime and appear in court.

One of the biggest misconceptions about identity theft, Mr. Allen says, is that most of it occurs on the Internet. Thieves often simply steal mail or paper documents, not digital files. Your personal information is in doctors' offices, with former and current employers, in banks, and at colleges or universities you've attended, Allen says. "You are as exposed for what you've done in the past as for what you do in the future."

You need not have even done anything foolish. Last month, ChoicePoint, a data-gathering company, announced it apparently was robbed of personal information for at least 145,000 people, including names, addresses, and Social Security numbers. The theft was an old-fashioned scam that used dummy companies and involved no computer legerdemain.

Next to that, computer hackers might seem like small potatoes. And some of them only send users annoying ads, says Curt Brooks, a technician at Tech Rescue, a computer installation and repair firm in suburban Boston. But some are more malicious - searching for credit-card or bank-account information to steal money.

His shop usually sees machines only after the spyware and adware have gotten out of hand. "We've seen computers that have 4,000 [secret] programs running" - picked up through everyday actions such as clicking on e-mail attachments, visiting websites, or sharing music files. In two or three hours - at $59 an hour - nearly any computer can be cleaned up.

"Phishing" scams are the most potent online hazard. People get e-mails saying they should verify their accounts at, say, eBay or PayPal (an online payment service). They click on a link that seems legitimate but is actually a dummy site. Once they enter personal data, such as their name, credit-card or bank-account number, and password, the thieves have it.

"There are some [phishing scams] that are so slick that law enforcement officers fall for them," says Jay Foley, co-executive director of the Identity Theft Resource Center (www.idtheftcenter.org) in San Diego, a nonprofit group. But no legitimate business would ask for such sensitive information in an e-mail. If in doubt, call the company, Mr. Foley says.