poutlook.exe vs. calendar.exe, etc.

[Guest stroochy]

I recently noticed that I have two separate programs to run calendar, tasks, notes. I see "poutlook.exe calendar" is the link to run what I assume is the Outlook calendar. But I also have something called simply calendar.exe. The same applies with tasks. When I try to run poutlook.exe from File Manager, nothing happens. I want to see if there is a difference between the two programs. Is this something to do with certification? I thought I had decertified my phone from AT&T/Cingular. Is there a registry setting that I can change to direct the phone to run the Outlook calendar instead of this "other" calendar?