Data Validation of Multiple Criteria with VBA

Dear Friends.

Attached an excel sheet.

I Will input either "BCOM" or "MCOM" text in Cells of Column A. And then Input in Column B in years "2016" or "2017". If any of these values are there in cells of Columns A and Columns B respectively, then all other cells should be allowed to be editable. Else, It should make other cells in all other columns locked restricting the user not to input any data further.

I don't want in formulas or Lists or using Data Validation settings. I need it in VBA Codes.

Request you to help.

Thank you.

Regards.
Perpectuals