sumifs, vlookup, multiple column rules

Hi,

In my spreadsheet I have 1 column with a range of different values, one with either "a" "b" or "c", one with "yes" or blank, and one with number 1-7.

Column 1 are the values i want to sum together but on some conditions...
- only include the value in the sum if the 3rd column is blank (omit if reads "yes")
- only sum together values which have the same number/letter in 2nd and 4th column (ie all A1's, all B5's etc)

I want to write a formula to sum these so that when the sort of the table changes the calculation doesn't change.

Workbook2.xlsx