Conditional Formatting by VBA, Highlight color when If conditions satisfied

[skhari]

Hi Experts

Please help with this task

I have two workbook (Please refer attachment)
1. StartPage.xlsm
2. CPBook.xlsm

In StartPage.xlsm I have a button where the action is triggered. On this button click
Open CPBook.xlsm, WorkSheet: CP
1. IF Cell A Range has some value and B Range is Null then Change Cell B into Red
2. IF Cell A, B and C has some value and D Range is Null then Change Cell D into Red
3. IF Cell A and B has some value and C and D Range is Null then Change C and D into Blue

The trigger action can be done only from the StartPage.xlsm

Please help me with coding

Thanks for your time.