440536 Unchecked Checkbox in Open-With Dialog for Unknown Files

In Windows XP "open with" dialog, I have never found an option to have default an unchecked checkbox for "Always use the selected program to open this kind of file" when opening an unknown file. reference: [login to view URL] I've altered my windows xp system so that when an unknown file is double clicked, you DO NOT have the option to select "Always use the selected program to open this kind of file" (where the checkbox doesn't exist, using resource hacker). However, if I add a key to Hkey Classes Root, and name it with the three letter extension of the file I want to work with, then all of a sudden I DO have the option to select "always use this program for this file type", AND IT IS UNCHECKED! So what I want to do, is add a context menu item to Unknown Files (I'd call it "Associate"), that will: 1. create the three letter extension key in HKCR 2. then run the "open with" dialog for said extension Please write a small program that will do this. This program would not need to be installed (I can add the item in the context menu for unknown filetypes), and not require anything that doesn't already come with WinXP SP2 or Windows 7. If it is as simple as a batch file, do not have the command-prompt-window flash on the screen when the batch file is run.