Alert/warnings when an elapsed time is reached

Hi
I have attched a sample workbook,

When the time required for is entered in column J column k counts down the time left to complete the job, the cell goes red with one
hour to go.

is it possible to do the following:-

When the half hour to go is reached warning alert message box is shown and or audio alert is sounded, but if the completed box is selected in column P the alerts are disabled and the time frozen in K ???

Regards


Peter

Hi

Has anybody any thoughts on this or part of this ?

any help would be appreiciated

Peter