Vista - Vista wakes up itself from Sleep/Hibernation every 10:00AM local t

Hello,

I have Windows Vista Ultimate 64-bit. In the last five weeks, I have noticed
that, whenever I leave my computer in Sleep or Hibernation mode, it wakes up
itself the next day exactly at 10:00:00 AM local time. From the Task
Scheduler, I disabled the UserTask-Roam task found on "Task Scheduler
Library\Microsoft\Windows\CertificateServicesClient" and all Media
Center-related tasks which I then suspected would be responsible for waking
up the computer automatically.
I still want my computer to wake up itself every Sunday 3:00 PM local time
to record a favorite TV show with a third-party HDTV program supplied with my
HDTV tuner card. (Such task requires that my computer be in either Sleep or
Hibernation mode, and I think it requires me to enable the SideShow AutoWake
task even though my desktop computer has no SideShow features.) But I don't
want my computer to wake up every day at 10:00 AM just to run something I
don't know what is.
Any help on this???