I used the link from the Tor newsletter to get the latest version of Tor. When I installed and then launched it, I got an alert that there was a Trojan virus. My antivirus killed it and it hasn't popped up again.
So, my question is - how did I get a Trojan virus from downloading Tor?
I have heard of antivirus software wrongly flagging Tor in the past because it's used by some viruses. That could be the case here.
You should check the digital signature of your downloaded Tor browser bundle file. There are some videos describing how to do that here under the heading "How to verify the digital signatures". It's also described here if you prefer to read.
If the signature is correct then it's almost certain you have a legitimate copy of Tor.
If the signature is incorrect then you've got yourself a bad copy of Tor, although it's not clear how.
