I've seen this problem from time to time. Windows Calendar in Vista would not remind even when in the options I select "Reminders should show when Windows Calendar is not running".
The problem started when I changed my computer name.
Going into the "taskschd.msc" would give an error. It's because I changed my computer name.
The solution is to just put my name back the way I had it.
Here's an old thread that tried alternative procedures, but none worked for me.
http://www.vistax64.com/vista-general/125194-windows-calendar-reminder-not-working.html
The problem started when I changed my computer name.
Going into the "taskschd.msc" would give an error. It's because I changed my computer name.
The solution is to just put my name back the way I had it.
Here's an old thread that tried alternative procedures, but none worked for me.
http://www.vistax64.com/vista-general/125194-windows-calendar-reminder-not-working.html