Sput,

 

One of the features of certain active anti-spyware programs is that they attempt to protect you from browser/homepage/searchpage hijackings.   Typically, they do so by taking as "default" your then-current homepage at the time you install them; and then, when they 'sense' that someone/something is attempting to change your home page, they will either call it to your attention (asking for your explicit consent to proceed, or allowing you to deny the action), or alternatively, they may simply disallow the change without further user input.  I'm not personally familiar with Ad-watch, but it appears to me that it was doing the latter.

 

to cite some other examples: 

I believe that Microsoft anti-spyware beta will, upon install, ask to make note of your [then current] browser pages, to help protect you from hijackings.

WinPatrol allows you the option to watch for changes in IE's home/search pages; and if you enable this option, it will alert you, and ask for your permission/denial, anytime changes are attempted.

SpyBot Search & Destroy, if you go to Advanced Mode / tools / IE tweaks,

allows you to simply "lock IE start page setting against user changes"

 

I am presuming that somewhere in Ad-watch, you can TELL it what home page you really want (Yahoo, Google, or whatever), and then, use the "automatic" feature to protect this page from being altered without your consent.