Here is a copy of a small worksheet .
aaabbbccccddddeeeeffff
3 a =REGEX.COUNT($A$1,"a")
3 b =REGEX.COUNT($A$1,"b")
4 c =REGEX.COUNT($A$1,"b")
4 d =REGEX.COUNT($A$1,"e")
4 e =REGEX.COUNT($A$1,"f")
3 a =REGEX.COUNT(A1,"a",FALSE)
4 b =REGEX.COUNT($A$1,"b",FALSE)
4 c =REGEX.COUNT($A$1,"c",FALSE)
4 d =REGEX.COUNT($A$1,"d",FALSE)
4 e =REGEX.COUNT($A$1,"e",FALSE)
4 f =REGEX.COUNT($A$1,"f",FALSE)
The REGEX.COUNT is part of the Morefunc Excel addin you can find the link below. There is true function that checks for upper or lower case or a false that will count both.
http://www.mrexcel.com/forum/showthread.php?t=126629
I hope that helps
mike in wisconsin