Hi there,
I just noticed a few days ago that I had the same problem than SkyWired, a cookie that wouldn't get deleted no matter what I tried with CCleaner.
I tried all the stuff previously mentionned, Killbox, Malewarebytes and so on.
The only way I could remove the two repertories in # C:\Documents and Settings\{username}\Application Data\Macromedia\Flash Player\#SharedObjects\{Randomword} and # C:\Documents and Settings\{username}\Application Data\Macromedia\Flash Player\macromedia.com\support\flashplayer\sys was to use SkyWired's technique with Unlocker :
I moved the files with unlocker in another repertory to the desktop, then move it to a USB device (a lousy 128M stick I never use) then I deleted everything on the USB stick
the two repertories were scanned (avg, spybot, A?, Malewarebytes, ...) and didn't appear as threats
so everything's well that ends well.
thanks for all the advice I found here