Holy cow, I wrote a book!
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.
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."