Match 2 criteria to find a third and add together

Hi,

I need a formula to find match two criteria and add the numbers that match these criteria together.

e.g if I am looking in a table to matc "user access issues" in column a and "major" in column c and they have three numbers that relate to those 2 specific criteria in column d i want these three numbers added together.

So in summary I need to match 2 criteria to look up certain numbers that relate to these criteria in another column and I want these added together.

Hope that makes sense. Willing to send the excel workbook if needed.

Thanks,

Sam