One if the drawbacks of the free version ok kirby alarm is only one pop up can exist at a time.
If you have accidently set the recurrence to every minute rather than very hour, then that would mean the program is going to pop up a note for every minute the alarm has been missed one at a time.
The easiest away to resolve it is to use task manager to kill kirbyalarm.exe and then delete the alarms.tps data file. This of course means that you will lose all of your alarms and they will need to be reentered.
If you have a lot of alarms, then can you please send me the alarms.tps file and I will remove the offending alarm. (don't forget to provide details of which one it is please)
I hope this helps. If not please let me know and I will be only too happy to help any way I can.
PS. The pro version of kirby alarm does not have the one alarm restriction and will allow multiple pop ups at the same time.
There are tons of other improvements. If you are interested check out http://www.kirbyfooty.com/html/kirby_alarm_pro.html