When you right click a file in Explorer you can have your application appear on the popup context menu by adding these registry settings:

    Add this key    
        HKCR\*\Shell\Open_With_MyApp

    and set its Default value to:
        Open With MyApp

    Add this key    
        HKCR\*\Shell\Open_With_MyApp\Command

    and set its Default value to the full path to you application. Example:
        x:\Path\MyApp.Exe %1

    Where MyApp is the name of your application.

Add an item to Windows Explorer context (right-click) menu easily – How to add them ?

  Add items to Windows Explorer Shell context menu easily with Explorer Context Menu. This powerful .Net component for your own, custom items appending to Windows Explorer context menu will add all your custom entries to the Explorer context menu. This .Net component and VB.NET support include detailed C# and VB.NET samples, tutorials , user-friendly manuals and support all you may need :

• Add items to Windows Explorer context menu to be shown on any Windows computer (all operating systems are supported – XP, Vista, Windows x64 , etc.)
• Add any type of items to Windows Explorer context menu to be shown in any way - with custom caption and your custom icon, as separator or sub-menu
• Add items of any types to Windows Explorer context menu to be shown for all files or shown only for computer files of particular type (for example, only for .DOC , .MP3,.WMA,.AAC , .MPG files)
• Add your program entries to Explorer Shell context menu, sub-menus, sub-menus of unlimited depth and even more
  

Windows Explorer Context Menu - is a powerful .Net framework component that support all you may need to add all your program items to Explorer Shell context menu - in a fast and a very easy way. Add all your application items to Explorer context menu right now – add items to context menu fast and exactly as you prefere :

Automatically Refresh File Lists
Change the value of UpdateMode in HKLM\System\CurrentControlSet\Control\Update from 01 to 00.

Display Thumbnails - Windows Explorer
To display icons that show thumbnails of the actual images, change the default value of HKCR\Paint.Picture\DefaultIcon to "%1".

Hide Files from View
To hide certain file types from appearing in Explorer, open HKCR\ .ext key where .ext is the file type to hide. Note the file type listed in the contents pane. Find the matching entry under HKCR and add this string value: NeverShowExt with a value of "". For example, to hide bitmap files find HKCR\ .bmp. The file type is Paint.Picture. Locate this under HKCR and add the above string value.

Customizing Folder Options Dialog
To customize the wording or settings that appear in the Folder Options dialog, drill down to the desired folder under HKLM\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder. You can change the wording by changing the Text property as well as the Checked and Default values.

Removing Start and Explorer Menu Options
Many of the options on the Start menu and in Explorer can be removed. To delete the option shown below, add the indicated Dword registry setting, with a value of 1, to HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer

To remove the following Find Menu options delete the indicated subkey from HKLM\Software\Microsoft\CurrentVersion\Explorer\FindExtensions

Your Own Context Menu Item
When you right click a file in Explorer you can have your application appear on the popup context menu by adding these registry settings:

    Add this key    
        HKCR\*\Shell\Open_With_MyApp

    and set its Default value to:
        Open With MyApp

    Add this key    
        HKCR\*\Shell\Open_With_MyApp\Command

    and set its Default value to the full path to you application. Example:
        x:\Path\MyApp.Exe %1

    Where MyApp is the name of your application. Because this method works only for Windows 95 / Windows 98 (not on XP, Vista, x64 - 64-bit Windows), to add items to Windows Explorer Shell context menu you should use, according to Microsoft guidelines, appropriate .Net component - Windows Explorer Context Menu. It will help to add your items to Explorer context menu - fast and easy.

Use Different Icon for Each Folder - Windows Explorer
You can do this with IE4 or later. Open the folder whose icon you want to change. Choose View | Folder Options, click the View tab, make sure Show all Files is selected under Hidden Files. Edit the Desktop.ini file with Notepad. If it doesn't exist, create it. Add the lines below. IconFile= is the path of the file whose icon you want to display. Many files have more than one icon. IconIndex specifies the number of the icon (they start at 0). To view various icons you can use, view the properties of any shortcut and click the Change Icon button. When you are done save your file. You must also make your folder a system folder. Select Run form the Start menu. Type ATTRIB +s "<path>" where <path> is the path of the folder you are customizing. Hit OK. Now view your new icon in Explorer (press F5 to refresh Explorer if it was already running).

[.ShellClassInfo]
    IconFile=C:\Windows\system\shell32.dll
    IconIndex=0

Using Command Line Switches
You can have Explorer open and look the way you want and display the folder you want. Just use the following command line switches. Note that there are a few cases documented in the Knowledge Base where they do not work.

So to get Windows XP to display folders like it does in Win2K, create a shortcut with the Target field set to Explorer /e,C:\.

Windows ME Slide Shows
You can use Windows ME Slide Show feature to displays a continuous series of images. Just copy your images (in .bmp, .jpg, .gif or .tif format) to a new folder. Rename your images in alphabetical order to control the order in which they are displayed. Right-click and empty portion of the folder and choose Customize This Forlder. Click Next, select Customize, check the Choose or edit an HTML template for this folder, click Next again then select Image Preview, click Next and Finish.

To start the slide show, open the folder and click the underlined slideshow text in Explorer's upper left corner. Slides advance automatically. However, click anywhere on the screen to advance them manually. Move the mouse and press any key to display a VCR like set of controls.