A couple of months back, out of the blue, my HTC Hero stopped notifying me on my upcoming calendar events. It didn’t even show upcoming events on the home screen widget, but it kept syncing new events without a problem.

I tried adding and re-adding the calendars I sync on the phone, turning on/off the notifications but nothing worked. I found a link to a guy who had the same problem, which ended up being caused by him force quitting the alarm service. But I had not done that, and either way it should’ve started working after a reboot if that were the case. Another guy managed to get his notifications working after doing a factory defaults reset.