Last year, faulty 1TB Seagate drives living in 21.5-inch and 27-inch iMacs purchased between May and July of 2011 were at the heart of Apple's HDD replacement program. Now, Cupertino has extended the initiative to encompass rigs sold between October 2009 and July 2011. Customers with an affected iMac are eligible to receive a free drive until April 12, 2013 or for three years after their desktop's original purchase date. Curious if your machine contains an afflicted hard drive? Simply visit the source link below and plug in your computer's serial number to find out. If you do need a replacement, an Apple Store or authorized service center will be happy to help -- just remember to back up your drive before parting with it.