Workbook Protection

I am using the following code to protect my workbook:

Please Login or Register  to view this content.

I stored it in the "ThisWorkbook" sheet in the VB Editor.

Problem is that if someone doesn't enable the macro on start up then they can edit the spreadsheets.

How do I protect the sheet per the above (or using a different code) so that the recipient of the spreadsheet cant bypass the protection?