Sound may not automatically switch to headphones using Microsoft Windows Vista on some Mac computers

When inserting headphones into the 3.5 mm headphone jack on the following Mac computers with Microsoft Windows Vista, the sound may not automatically switch to the headphones. MacBook (13-inch, Late 2009) MacBook Pro (13-inch, Mid 2009) MacBook Pro (13-inch, Mid 2010) MacBook Pro (15-inch, 2.53GHz, Mid 2009) MacBook Pro (15-inch, Mid 2009) MacBook Pro (15-inch, Mid 2010) MacBook Pro (17-inch, Mid 2010) iMac (Late 2009)