New to VBA - VBA Before Save & Before Email

Hi Everyone,

I hope someone is able to help me and apologies if i don't explain this very well but i'm in the process of creating a user interactive form on Excel. We used to have this form on a word document but as a few fields used to be left blank i'd like to make it so that the form cannot be submitted (i.e beforesave or beforeemail) unless the information is completely filled in.

Any field that has a red * is deemed to be mandatory and must be completed.

There are also 2 types of combobox on the form, 1 for Cost Centre & the other for GL. Is it possible to make the Cost Centre and GL mandatory for completion only if the rest of that row has cells filled in? So, ComoBox1 & ComboBox6 are only mandatory if cells B45 - F45 are filled?

Thanks in advance!