Live scanners:
PC Tools Spyware doctor unregistered
Spybot S &D Resident
Avast Antivirus
Zonealarm firewall
Windows defender
Spyware blaster (I don’t think it is a live scanner but it somehow blocks things according to download.com)

Every week scanning:
Spybot S&D
Spyware Doctor unregistered (I manually delete what I find with this)

Every month scanning:
Avast! antivirus

Do I really need windows defender if I have all these other things?
I just disabled Windows Defender and I have received a significant speed boost.