"I have tried Avira myself but noticed that everything has to be scheduled on it, scans, updates, etc."
That's not correct.
Avira does realtime scanning, updates can be scheduled, but you can also do a manual update, if needed.
Avira, also the free version, includes Boot-Sector scanning on all attached drives, MBR-scanning and searching for rootkits.
So I guess, it must have been a quite old version, you've tested.