No single product is 100% foolproof and can detect and remove all threats at any given time. The security community is in a constant state of change as new malware infections appear. Each vendor has its own definition of what constitutes spyware and scanning your computer using different criteria will yield different results. The fact that each program has its own definition files means that some malware may be picked up by one that could be missed by another. Thus, a multi-layered defense using several anti-spyware products
(including an effective firewall) to supplement your anti-virus
provides the most complete protection.
Instead of Ad-aware, I would recommend using SUPERAntiSpyware Free
The free version does not run in real-time mode...a purchased upgrade to the "Professional" version is required before this option can be activated. See Free vs Pro Comparison Features