Letters with accent marks

Any ideas?

I have a textBox that users will be entering data into and most likely
they will not bother to write the accent marks over the correct letters.
When performing the search I need a way to look at the words in the
database and say does it have a accent mark over it and if so ignore it
and render it as a, e, i, o, u. I tried to copy and paste these letters
with accent marks into the file in order to test for them but the
program (putty) doesnt recognize them and renders a bunch of random
letters.

Any idea how to test for i with an accent mark, a with an accent mark,
etc…