Saw similar thread on Treo Pro:

I don't have any alarms set on clocks and alarms page, but I still get an alarm (same time as one that I used to have set).

I've used Mem Maid to clean up notifications w/o out luck.

Sometimes I'll use Mem Maid to completely delete the registry:

HKLM/software/microsoft/clock . It has subkeys for 0,1,2 (three individual alarms.

Anyway, if you delete it it generates itself w/ default blank values.

Sometimes that has worked, and I've actually seen the Ghost Alarm values in the old clock keys.

It's kind of hard to get a handle on this, but sometimes neither of the above solutions will eliminate the ghost alarm. Sometimes it seems to magically reappear when I think I've fixed the problem. Where does it come from?