Mujahid,
If you are talking about Windev then you can use the count function of the table and define it in the details of the colomn. When there are no checkboxes checked the counter is 0 when there are 1 or more checkboxes checked the counter is the total of checkboxes checked. Then you can enter somewhere in your code.
IF COL_Checked[rowCount] > 0 THEN
HDR_Check = True
ELSE
HDR_Check = False
END