I have Avast 2.74R0 (service kit 1.41) on my Mac (running Mac OSX 10.4.11). I can't uninstall avast. I've tried all the tips I've previously seen on this site. The quit commands are greyed out and it is not possible to drop and drag to the trash. I've checked preferences and the "persistent" box is not ticked. So I'm stuck! Any ideas?