Visual Studio 2015 Update 3 - Setup Blocked

I faced a similar if not the same issue. I installed VS2015 with Update 3. There was no other VS version or edition in the PC - so you can say this is a fresh install. On starting VS, it prompted me to get KB3165756 (14.0.25431.0) and the next thing I got was: -

"Setup Blocked - Update 3 requires a member of the Visual Studio 2015 family to be present or is blocked by another condition on your computer"

Here is what I did to get around the problem -

1. From the command prompt, type "vs14-kb3165756 /uninstall". (Don't use the /repair option as this won't work.)
2. Choose Repair.
3. Let it run until finish.

Hope this helps.

You've downloaded the offline installer for the Update. This offline installer will update a previous version of Visual studio 2015 to Update 3. Major Visual Studio versions are installed side-by-side. So your 2013 installation will be left untouched by the 2015 update installer

You'll need to download the offline installer of "Visual Studio 2015 with Update 3" or first install "Visual Studio 2015 RTM" and then apply the update you've downloaded.

Solved by running the Original installation ISO. Setup auto-detect what will be updated, what will be replaced before starting the installation/upgrades (without touching what it's already installed).