are you using a 3rd party Task Killer?

 

Ok, you really don't need that. That app was designed when the majority of users were on 1.6 and at that point, it was a worthy addition.

Use the in built task manager on the S2 if needed as that doesn't include important apps running in the background.

I think what is probably happening is that you are killing all apps at some point throughout the day and that includes any clock that you are using for your alarm.

 

+1 to not using task killers.

I use a great Tasker profile for my alarm, more reliable than the inbuilt Samsung one (which sometimes failed on the SGSI, although I've not heard too much of that on the SGSII in the absence of task killers).

 

this maybe a stupid question but you don't have repeat day every work day or weekly on do you?

 

that was my initial thought as well...