VB Code Help

Hello,

I am getting an error when i am doing the above mentioned code.

My requirement is if in an excel file(abc) i have a base data of huge numbers
and in another excel file (def) in a particular column (ex: Column c) i enter a number so the macro should check the number entered by me in the base file (1st file) and through an error if the number does not match the base file.

The error message should pop up saying number incorrect / number not present in database.

Could you help me on this.