Mystery: Install during Build

[thirteentwenty]

I've just updated a project that I was working on a few months ago, I went about my clean/build routine where I select "Clean Solution" then build the solution over. It consists of 3 projects, 2 exe's one for the for the user and one for the server. The last one is the installer.

Here's what happened...

Clean Solution ... Clean OK
Build project one... Build OK
Build project two... Build OK
Build Installer... install <click cancel> try build again... Build OK

I was wondering if anyone has come across this before and if so how did they stop it?...

Mind you, the only things that have changed were the tab orders on a few forms and a couple of print routines... and it didn't do this the last time I did a build. But that was a couple of months ago. Nor has it done this on anything that I'm currently working on.

I'm kind of at a loss right now

Sys info:
OS Vista Ultimate SP1 (32bit if its important) current on all updates (sans the language packs)
VS2005 SP1 for Vista (I think is current also)

Any suggestions, insight, ideas or even good ole mockery might help...

Edit: P.S. If this is in the wrong place, my bad, please feel free to move!