Microsoft has rolled out a new update that changes the AutoRun feature on older versions of Windows. Optical media like CDs and DVDs will still work normally, but for USB flash drives and other removable media the software giant has disabled the feature to make it harder to spread viruses. The patch has been part of Windows 7 and now it's being rolled out to previous versions of Windows as well.
After some years of telling users to disable the feature - but providing no easy way to do it - Microsoft re-engineered AutoRun in Windows 7, preventing viruses from making use of it for USB keys and other removable media. And now, an update is being pushed to users of older versions of the OS through Windows Update which should close the loophole for good.
This patch - which essentially back-ports the Windows 7 changes to Server 2008 and earlier operating systems - was originally released in November 2009, but it was made an optional download to satisfy the needs of business users. Only now is it being pushed out to everyone automatically.