I did all the things you wrote. The reportagain was only 1 sec. on the screen. After the PC started again there was the message: the volume is undamaged.
Scanning of the C-disk still stops at 42,3%
Done chkdsk C: /F. The report came on in a flash, so I couldn't read it. I used CCleaner after that, not for the regsiter, and did chkdsk again. Result: scanninf stops at 42,3% and now 11748 files.