Yes, you can change it there. In "File types", if you select a disc drive (I don't know with what name it appears on your XP, because I'm using a French version), you will see a button "advanced" where it is possible to define new actions to be taken on this item AND to define/change the default one. For a drive, there was no action foreseen like "open" or "find". I added "open" and "find" was added at the same time (?). I tried (and succeeded) in changing the default action to "find" for the object "drives"; the result was the search window on double-click. I reset it to "open" (with explorer.exe) and all went back as before. But I cannot understand how this default action can have been changed spontaneously.