|It adds an air of politeness to a post if you actually ask a question, maybe even throwing in a "Please" and/or a "Thank you" instead of just telling us us what you want.|
Would you walk into a co-worker's office or a friend's house and just blurt out that you want something or would you say something like "Hey, could you help me with this..."?
There's no reason that it should be any different in a forum such as this one. We're all just volunteers, giving of our free time, trying to help out. Politeness goes a long way.
As to your question, I'm not sure why you need the code. If you want to see if a name is repeated, why not just use COUNTIF?
For example, with your list in A1:A100, and tom in A1, try:
=IF(COUNTIF($A$1:$A$100,A1)>1, A1 & " is repeated")
Since your example has "tom" listed twice, the formula above will return:
tom is repeated
If there is a reason that the code is required, let us know and we'll see what else we can offer.