If you are using a Data Valadation drop down try this.
Sort your validation list and at the beginning of the A's enter a single A,
do the same for the beginning of the B's and all the way through to the Z's.
Click in the cell that has the drop down validation and type in the letter
of the list you desire... say you type in an O. DO NOT hit enter... leave
the cell in the edit mode (still selected) and now hit your down arrow.
Should take you to the O which is the top of the O list of selections.
HTH
Regards,
Howard