Ask you advocate.

I lost my Social Security card. Can I get a new number? I'm afraid someone will find the card and ruin my credit.

--T. Wu

New York City

Unfortunately, you can't get a new Social Security number. Unless you can provide evidence that someone is using your number, the Social Security Administration won't grant this request. Furthermore, getting a new number could pose additional problems. If your old credit information is not linked to the new number, the lack of credit history under your new number might make it hard for you to obtain additional credit. Some lenders will want to see past payment history before extending credit or granting a loan. However, you can apply for a replacement card free of charge. You'll have to contact the Social Security Administration and ask for form SS-5. Go to www.socialsecurity.gov/online/ss-5.pdf to download this form.

Also contact one of the three credit-reporting agencies and ask for a fraud alert. This will prompt any company accessing your report to confirm your identification before granting credit. Finally, once you've received your replacement card, stash it in a safe place. Never carry it in your wallet. Memorize the number so that you don't have to carry the card with you.

If you suspect someone is using your number, file a complaint with the Federal Trade Commission. Also, check your Social Security record and make sure your information is correct by calling 800-772-1213.