https://www.brightfort.com/spywareblaster.html
All I know is that it runs in the "background," with no scanning, etc., needed. I update whenever I remember to do so.
I guess you are the same as me with regard to the upgrades. I had the automatic upgrade checked on my Win7 for the MBAM and it automatically upgraded to the new version, which I do not like. My Vista still has the previous MBAM and I too will keep it as long as it updates. The new one is just too "bloated" for my needs. I guess these free versions are always trying to get you to buy the paid-for versions.