Apple has launched a repair program called "MacBook Repair Extension Program for Hard Drive Issues." As the name suggests, it is intended to deal with a batch of MacBooks that have had a specific hard drive issue. Under the program, Apple will replace the hard drive for free on affected systems.
"Apple has determined that a very small percentage of hard drives that were used in MacBook systems, sold between approximately May 2006 and December 2007, may fail under certain conditions," the company said on its Web site.
Apple has stipulated that only MacBooks that get the flashing question mark emblem when they try to boot up need be concerned about the problem. If your MacBook falls under the date range listed above ad you get the flashing question mark, you are asked to bring your MacBook to either an Apple Store or an Apple Authorized Service Provider.
If your MacBook falls under the above date range but you do not get the flashing question mark (i.e. it boots up just fine), Apple said you do not have to take in your MacBook.
Apple is also offering to reimburse customers that already paid for an out-of-warranty repair for this problem, noting, "Apple will contact affected customers (where contact information is available) with details on the reimbursement process. If you believe that you paid for a repair covered by this program and you have not been contacted, you may contact Apple Technical Support."
You can get more information at the repair extension Web site, which also has information on how to identify the date of your system.