Ok while I am in a bad mood.

I just let ccleaner run on my machine (a tool to delete unwanted crap from the harddisk and clean the windows registry).
It told me that there are 11365 files in the:
C:UsersusernameAppDataLocalMicrosoftWindowsTemporary Internet Files
Most of them with 0 kb in size. They are named like
...  0Q9P0A9IapiCA022NV4.xml
I checked where they come from (I never use Internet explorer). And guess what. It's Poser that creates those files (I guess it's Flash that causes this).
You can't see those files by just watching the directory in windows explorer. I just can see them if I let Ccleaner analyse my PC.
Anyway I let CC delete those files and forget about them.