Find excel workbook protect-unprotect method that works on Excel 2013 version

I attach two Excel spreadsheets that were created in Excel 2007. First one uses workbook_open (userinterfaceonly) procedure to keep all sheets protected when various VBA modules are run; the second one uses workbook_sheetactivate (userinterfaceonly) procedure to achieve similar effect. However, both spreadsheets give 'wrong password error' when used on Excel 2013 and when a standard VBA is run that includes: [login to view URL] Password:="passwordhere" command. I added an 'unprotect workbook' button to make it easier to replicate the problem. The task is: 1) to explain why these spreadsheets (created in Excel 2007) do not unprotect/protect in Excel 2013. 2) to find a solution to this problem, to send a working spreadsheet and to give instructions on how to modify the original files (it is essential to this project that I can replicate your solution). 3) once you have a solution check whether there are any problems with protect/unprotect sheet on Excel 2013. If yes then these have to be fixed as well. NOTE: I noticed that often with the workbook_sheetactivate procedure, the workbook can by unprotected but only if I do not change a tab. Once I select a different tab and then press 'workbook unprotect' button then an error pops-up. All passwords (VBA, sheet, workbook) are included in the spreadsheets. The lowest bid with the lowest delivery time will win this project. Thanks.