How to sum the totals on one column, if two other columns are true?

Hi.

(Excel 2003 on windows XP.)

I need to SUM the cells in column J when column E has the word "yes" and the range N:R has a letter "w" in one of the columns. Only one of the N:R columns will have an entry on any one row and it may not necessarily be a "W".

I have Googled, and being a beginner I don't comprehend the result! Some people were talking about using an add in, but I won't be allowed to add software to our PC's. Could someone give me a pointer to the correct function please?

An example of some data...

A B . .  E  . J  . N O P Q R
x x . . Yes . 12 . . . . w .
x x . . No  . 3  . . . . w .
x x . . Yes . 1  . . . . . a
x x . . Yes . 5  . w . . . .

Thanks in advance.