But navigate to C:\Program Files\Lavasoft\AdAware (there could be a couple of folders here) but what you're looking for is a file that's actually labelled "defs", and ther may be another one called "defs.old" (which is used as a backup.) Delete the newer one, rename the old one by removing the "old", then re-open the program. Try a scan - just for a few seconds. If it works, try updating.