When you right-click a file and choose the Open With command, or click the Choose Program.... sub-menu, Notepad may launch automatically (the selected file opens with Notepad), rather than Windows displaying the Choose the program dialog box.


Follow these steps to resolve the problem:

Click Start, Run. Type REGEDIT and press Enter.

Navigate to the following location:

HKEY_CLASSES_ROOT \ Unknown \ shell

Backup the key by exporting to a REG file.

In the right-pane, set the (default) value to openas

Then, navigate to:

HKEY_CLASSES_ROOT \ Unknown \ shell \ openas \ command

In the right-pane, set the (default) value to the following:

rundll32.exe shell32.dll,OpenAs_RunDLL %1

Close REGEDIT