Excel Removing characters after

I have a table with many codes (4800) ie
AB
AC.2
AC.23
AAD.3
etc
I need to sort them & remove duplicates of the character before the "."
So I would finish with
AB
AC
AAD
Hope you are still with me.
So I need to remove all characters after the "."
I am not sure what that would do to the the first item in the list as there was no "."
If this was a one off I would do it manually, but I think I will need to do this a few times in a year. Any ideas

Use the "edit and replace" fucnction [Ctrl +H]

Find what : ".*"
Replace with: ""

This will remove the dot and all after it.

RichA Thanks for that.
I found a nice piece of 30 day freeware, Removes so many different user definables & it put an icon on the toolbar.