A customer ran into the following problem:
I was trying to add another email account to Outlook, and the instructions say that I should go to the mail icon in the Control Panel, which to my surprise is nowhere to be found! How can I figure out what went wrong?
A little bit of psychic debugging will solve this.
The customer was running Windows Vista, 64-bit edition. On 64-bit versions of Windows XP and Windows Vista, the Control Panel shows only 64-bit control panels. The 32-bit control panels are off in a separate 32-bit control panel, which you can find by clicking the View 32-bit Control Panel Items icon.
The separation of 32-bit and 64-bit control panels is an unfortunate consequence of the rule that 64-bit processes cannot load 32-bit DLLs and vice versa. On 64-bit Windows, Explorer is a 64-bit process, which means that it can't load traditional 32-bit control panels. (Recall that control panel applications run as DLLs inside the host process.) Therefore, Explorer has to pass off the work of working with 32-bit control panel applications to a 32-bit alter ego process.
Fortunately, Windows 7 no longer segregates control panel applications by bitness: They all appear in the main Control Panel. This was done by running a puppet 32-bit copy of the Control Panel behind the scenes and making the puppet do the main Control panel's bidding whenever it needed to access information about 32-bit control panel applications.
"Hey, go enumerate the 32-bit control panel applications for me."
"Hey, go get the icon for this 32-bit control panel application."
"Hey, go launch this 32-bit control panel application."
"Hey, go make me a sandwich."
"Hey, give me a backrub."