Need forumul for counting lines of servers but not duplicates

[Stormy4757]

Hi all,


I have a tight deadline and was wondering if anyone knows how to write a forumula for me.
I have a spreadsheet containing 62,293 lines of data. In column A I have the names of servers. I need a count of these servers, but some are duplicates. Obviously I don't want to count those. I tried the “Remove Duplicates” under the Data Tab but it is greyed out. Why? Is there a simple way to do this?