To insure the best scan and adware cleaning, you should make a Full Scan, at least in the first time.

It's preferred not run other programs in the background and let the Ad-Aware to remove all the spyware, Warms and Trojan Horses from your computer without disruption. A full scan takes approximately 15-10 minutes.
Any time you can stop the scan by clicking the Stop Scan.

If the computer is clean and have no spywares, you will get a message: No malicious objects were detected.
If Ad-Aware will detected a malicious objects, You Should click on Perform Action Now and the program Will quarantine the malicious objects.