Question: Because I haven't used my oldest credit card for a year, HSBC says it's closing the account. I'm afraid this will hurt my credit score. Help! -- Nevena Georgieva, Chicago

Answer: Credit-card companies lose money on dormant accounts, and as they feel the economic pinch, they're more apt to close them. Unfortunately, as you suspected, closing your oldest card can lower your credit score. The length of time your accounts have been open is the third most heavily weighed factor in your FICO score (after timeliness of payments and the amount you owe). Plus, eliminating a card reduces your available credit, which could also lower your score.

I contacted HSBC, and after checking your credit history, the bank agreed to reopen your card. Spokeswoman Cindy Savio says HSBC will consider reopening inactive accounts, especially if the account was recently closed and the customer had been with the bank for a long time.

Tip: If you have a lot of other cards and a credit score of 720 or higher, one closure won't have much effect on your score. But if you have a slim credit history and few cards, it's wise to make sure your oldest accounts stay active. So use your card at least once every three or four months. Then be sure to pay it off every month so you're not racking up big interest charges.

Having a financial nightmare? E-mail Donna Rosato at money_helps@moneymail.com.