Continuing what Dave-So said, yes, it is known that all spyware sweepers find different things. Even the makers advise using more than one product, since they can't keep up with all of the various crapware products out there. (It's different than viral outbreaks, a virus spreads, whereas you normally receive crapware downloads via a singular website. There are so many different variants that its a matter of luck for a sweeper writer to locate it.) I just use SpyBot alone since it's free, and I tend not to go near sites that have spyware problems these days. I just leave it running in my system tray, and it blocks what it gets to. I also play a lot with my browser settings to prevent ActiveX controls, Java programs, etc. from downloading and running. I only stuff to run from trusted sites. As far as AVG, it's a great product. If you allow it to sit in the system tray, it will autodownload updates every day, and you can set it to scan the computer as often as you like. I have mine set to begin a full system scan at 4a.m. every day. It usually takes about 2 hours to cover both of my hard disks. The best part of the software? It's totally free for personal use. You can purchase a copy with a little more functionality, but it isn't necessary. The updates are even free!