activate or desactivate checkbox depending by the subject into combobox

[jdasp49]

hi
I have a userfotm for record sales.
I use a combobox for the months of the year.
when the month comes to the end I close the registers through the checkbox "Close".
By changing for the next month (by combobox), I wanted that the checkbox turns off automatically. How do I that?
Thank in advence

[Medpack]

Post a sample workbook...

[jdasp49]

Hi
Medpack
Here the samplescarSales2Forum.xlsm