This question already has an answer here:
I noticed that I lost 40 reputation points on Stack Overflow today. I checked my reputation history and this is the reason it gave me:
-10 19 mins ago removed User was removed
-30 19 mins ago removed Where is Visual Studio Express?
I did answer a question about where Visual Studio was located about a week or so ago, but I can't find it now.
I'm guessing that the original person who asked the question deleted his account and so all his questions got deleted as well, but why remove the reputation on the answer?