Thank you both for the replies, I appreciate your help with understanding this better.
I wish the definition by MS was a little more clear as to if it BLOCKS malware or just REMOVES it, if detected.
"Windows AntiSpyware (Beta) is a security technology that HELPS PROTECT Windows users from spyware and other potentially unwanted software".
and " Microsoft researchers quickly develop methods to COUNTERACT these threats, and updates are automatically downloaded to your PC so you stay up to date".
I interpret "helps protect" and "counteract" as meaning that it PREVENTS spyware from getting on the machine. I guess this is why I thought (as you are saying incorrectly) that it might be considered a firewall.
So to clarify and finalize, you both saying that it doesn't block malware, it just removes it, correct ?