Spybot - Search & Destroy 22.214.171.124? As far as I know that is the latest and said to be compatible with Vista. I run it with Vista Ultimate without issues. If Vista UAC is enabled maybe it would install if disabled. Some are having issues with UAC enabled while installing software.
Hope this helps.
Having used SpyBot for some years without difficulty (with XP), I disregarded the CNET Editor's difficulty in recommending the current version of SpyBot Search and Destroy.
I downloaded it to my new Toshiba laptop, with Vista. And, as I had been forewarned, it froze up (stopped responding) during the installation. I had to uninstall it and do a System Restore.
Just wanted to put the word out that it happened to me too. So... be careful, y'all.