I loaded Ad-Aware 2007 Free on several computers & was having a problem on only one.
What I recalled, was that when I first loaded the program, I was able to get at least
one scan in. At some point in time, I could not complete either a FULL or SMART scan.
I think I found a clue or possible solution.
When I looked in the directory where the program was installed,
I happened to notice that there was a file which was saved as a BAK file.
(Filename: Ad-Aware 2007.exe.bak).
I performed a MS-DOS File Compare on this file & the working file,
Ad-Aware.exe.
While both files have the same filesize they did not compare successfully.
I decided to put the Ad-Aware.exe file on the side.
Then I copied the .bak file to Ad-Aware.exe.
When I opened up Ad-Aware, I did not perform any UPDATEs initially.
It ran both a SMART & FULL scans.
Then I performed an UPDATE.
It still runs. I think that one of the earlier updates might have been corrupted.
I've attached a rough procedure on what to do.