Versions of Windows older than 7 were prone to infections due to one major reason – AUTORUN! Whenever you insert a USB flash drive that has an infected autorun.inf file, your computer gets infected. This, however won’t happen from now on thanks to an update from Microsoft.
If you are using Windows 2000/XP/Vista or Server 2003/2008, you’ll be receiving an automatic update with the number 967940. This update will back port the Autorun behaviour of Windows 7, which means there won’t be autorun for USB flash drives, thus reducing odds of your computer getting infected. (Autorun will still work for CDs and DVDs)
If for some reason you aren’t able to get Windows Updates automatically, download and install the update featured in this page, to get the functionality on your PC.