1. You download it as a ZIP. This should be unzipped and you are good to go.
You can EXTRACT the contents of an installer *.EXE if you want the bit that works but not the registry etc. installation gunk.
Perhaps you failed to extract something crucial.
2. Did you "run the command line inside windows" by launching Start => RUN
and typing the command in the little box ?
Some things work that way, others don't
I have just downloaded from MajorGeeks as per
http://forum.piriform.com/index.php?showtopic=29886'>http://forum.piriform.com/index.php?showtopic=29886
I unzipped and dragged a link to my desktop and the properties show the command line was
D:\Zap\CC\CCleaner.exe
I amended to read
D:\Zap\CC\CCleaner.exe /AUTO
I double clicked and the CCleaner icon appeared as usual in the notification tray, and showed activity for about 10 seconds.
What I downloaded and unzipped has properties showing
Version 2.35.0.1223 and modified 26 August 2010, 15:23:36
I guess a new one is on its way.
My first guess was User error by those trying CC for the first time.
My Fall-Back guess is that you may have received a partial/corrupted download when the Piriform server was on the way out, see
http://forum.piriform.com/index.php?showtopic=29886
Regards
Alan