After installation, it automatically did a "Quick Scan" of the PC, not finding any threats... which I figured it wouldn't. I've set it up as I had AVG, to do a deep scan nightly at 2AM though, just to see if it might catch something...AVG always came up clear, except for one time, after an update, it was showing XChat as am "infection", which turned out to be a "false positive".
Microsoft has the product as a seperate, free download, but you have to get it from Microsoft's site. It won't be included in any version of Windows by default, so Microsoft can avoid any anti-trust suits. Still, IF it turns out to be a reliable product, companies like AVG, Norton, Eset, etc... might need to pay attention... especially from this blog post entitled
"Is The PC Security Business About To Go Out Of Business?" on Lockergnome.com.
Ignore this post if you have a Mac or are running Linux... I'll confess, you are already protected for the most part! ;-)