Well I recommend u one gr8 combination : Avast 4.7 + Spybot - Search n Destroy = Complete peace of mind Others sucks I try all n this is d last good combo
Yes, as anand said, stick to AVG Antispyware. But are you using free version or paid version? If it is a free version, automatic updates won't work. You need to manually update by clicking "Update Now" in the main window. If it is paid version, you need not worry about updates. It does automatically.