I have a problem that I have not found a suitable solution to:

I have a list of all possible combinations of two letters. (i.e. AA,
Aa,....ZZ,Zz)
NOTE that there are four possibilities for any arangement of the letters-
AA Aa aA aa

Each of these combinations has a different value assigned to it in the next
column.
AA 1
Aa 2
aA 3
aa 4

So, how can I use my table to "lookup" the values of any of the combinatios?
Also, it should be noted that not ALL of the values in the cells are two
characters long..... A and a and B and b are in this list as well.

What I need to be able to do is simply type into a cell what I want to
"lookup" and have it spit out the value.

This is formula I have been using but it does not work with all possibilities.
=IF(EXACT(E2761,VLOOKUP(E2761,$B$1:$C$2756,1,FALSE ))=FALSE,VLOOKUP(E2761,$B$1:$C$2756,2,FALSE),"No MATCH")

Basically it works but can only return certain values:

"AA" will return a value as will "aa" but "Aa" or "aA" will not.....
why?