When ever you plug a usb device to the system or insert a cd/dvd disk, The windows Autorun Run utility runs and displays certain options like Open files to view, Play, Do nothing etc.
Although this is good utility provided by windows operating system, It is sometimes very dangerous too. When A virus infected Usb drive or Cd is plugged into the system, the virus gets a chance to attack your operating system by running automatically when you plug your device in. So, for this safety purpose, we need to Disable this Autorun feature in windows.
Follow the below steps and ensure your systems safety.

1) Click Start –> Run and type  GPEDIT.MSC  –  This opens Group Policy editor window.
2) On the left side –> expand  Computer Configuration–> Administrative Templates–> System.
3)  Locate the entry for Turn autoplay off on the right side.
4) Double click it and select “Enabled”
For any further assistance to Disable Cd Autorun view the sample screen shot below.

Enjoy...