AutoPlay (also known as AutoRun) is a feature that automatically runs a program on a removable drive or on a CD/DVD after connecting/inserting it. Most automation tasks are specified in a special file named autorun.inf.
AutoPlay is a convenient feature, but it also means that viruses and malware make heavy use of such automation by launching or installing programs without you ever noticing it. That's why most security-aware people tend to disable it completely.
In addition to executing actions specified in autorun.inf files, Windows asks what to do next after you insert a movie disc (Video DVD, Video CD, etc) or an audio disc.
Windows XP and Vista users should apply an update that prevents launching programs automatically from removable and network drives (links are later in the article). If Windows Update is properly configured, the patch should already be applied.
Windows 7 and 8 have the feature disabled by default.
If you want to quickly disable AutoPlay for all drives, restore AutoPlay defaults, disable or enable autorun.inf blocking, use the ControlAutoRun program on my other site, help.artaro.eu.
Configuring AutoPlay for CD/DVD drives and removable drives in Windows XP
In Windows XP, you must set autorun preferences for each CD/DVD drive and removable drive separately.
That is, unless you have applied Microsoft's optional update from February, 2011 that disables autorun for everything except CD and DVD drives. This update is meant to stop wide-spread malware attacks that misuse USB and network drives.
You can download the KB971029 update for Windows XP here.
To configure AutoRun/AutoPlay for devices manually, open Windows Explorer (press Windows Key+E on your keyboard) and right-click your CD/DVD drive or a removable drive. Then click Properties.
Next, click AutoPlay tab. If you open properties for a fixed or network drive, there is no such tab.
In the first combo box there are several media types available - Music files, Pictures, Video files, Mixed content, Music CD, DVD movie, HD DVD movie, etc.
You must select an AutoPlay action for all types available for each and every CD/DVD drive and removable drive. This is tedious, but it pays off in enhancing security. 
If you want to be asked for an action every time you insert a CD, DVD or a removable drive, select Prompt me each time to choose an action for each content type. For example, if you insert a DVD movie you will be asked whether you want to play the movie with Windows Media Player, open the contents of the DVD in Windows Explorer, or do nothing.
To prevent automatic questions after inserting a disc or a removable drive, click to select the Select an action to perform option and then click Take no action for each content type.
You can also select some automatic action for DVD or CD movies (for example, Play using Windows Media Player).
Always select either Take no action or Open folder to view files using Windows Explorer for Mixed content in Windows XP!
After setting actions for all content types, click OK button.
Using AutoPlay configuration in Windows Vista, 7 and 8
Windows Vista users should first apply Microsoft's optional update from February, 2011 that disables autorun for everything except CD and DVD drives. This update is meant to stop wide-spread malware attacks that misuse USB and network drives.
You can download the KB971029 update for 32-bit (x86) Windows Vista here.
You can download the KB971029 update for 64-bit (x64) Windows Vista here.
To configure AutoPlay in Windows Vista or 7, open Start menu by clicking Start button or pressing Windows Key on your keyboard. Type "autoplay" in Search box and click Autoplay.
In Windows 8, open Settings Search using keyboard shortcut Windows Key+W, type "autoplay" in Search box and click
To disable AutoPlay/AutoRun completely in Windows Vista, 7 and 8, clear the Use AutoPlay for all media and devices check box. Click Save to close the window.
If you do not want to be that restrictive about automatic actions, use the following configuration instead. First, make sure the Use AutoPlay for all media and devices check box is turned on.
Then select Take no action for the following items:
- Pictures,
- Video files,
- Audio files,
- Blank CD,
- Blank DVD,
- Blank BD ,
- Mixed content.
This disables AutoPlay popups in case you insert a blank disc or connect an external or removable device such as USB Flash Disks or external hard drives with some of the listed content on them.
Windows 8 adds two new sections - Removable drives and Camera Storage. The first one should be set to Take no action to prevent malware from starting automatically.
If you import photos and videos right from camera, you can configure Memory card so that import dialog appears automatically upon connection. Appropriate actions are listed for each program that supports the function.
Set your own preferred programs for Audio CD, Enhanced audio CD, DVD movie, Enhanced DVD movie, Blu-ray disc movie, DVD-Audio, Video CD and Super Video CD.
I've chosen Play <media type> using Windows Media Player in this example - Blu-ray disc movie and DVD-Audio are disabled (Take no action) because there's no device capable of playing them on my computer.
Finally, select your preferred action for Software and games. To prevent potential malware from running automatically, I recommend just opening the folder or taking no action at all - you can launch installed games via Start menu and install software using Windows Explorer (just double-click the CD/DVD drive and automatic actions run).
Click Save to apply changes.
