Blocking of VBa templates

I've created a simple form that tells me date, date, OS, and Type. When my user tries to change some of it, it does not work, so I progame to stop the data change, but when my client selects all the cells in the worksheet and presses it deletes everything! I would like to know how to block and it does not delete the celexcs, I do not want to save the worksheet only to block the action of excluscadastraments because he would have been using all day registration?