Let's try the usb image and checkdisk util.
Next download
NTBR_USB.exe and save it to your hard drive. With the USB device attached, double click the exe to run it.
Verify that the drive letter shown is the same as assigned by Windows, then click OK.
Once the image is written to the device, you will be prompted to reboot ~ do not reboot and instead remove the device.
Insert the bootable device in the ailing computer and start it, then use the appropriate F key to access the boot menu where you can choose to boot from USB.
You should be presented with a boot screen - select usb and press Enter to boot to the device.
After a warning screen there is a keyboard language options screen - press Enter to leave it at EN-US.
You should now be at the Tool options screen.
Type
5 then hit Enter to choose the command prompt.
This should put you at an X:\>prompt ~ X: is the ramdrive (temporary drive space in memory).
Type the following bolded command then hit Enter to start the checkdisk utility.
tools\ntfs4dos\chkdsk
When checkdisk starts, it will say "Drücken Sie die [ENTER] Taste um die Laufwerke zu prüfen" which translates to "Press the [ENTER] key to check the drives"
Press Enter to allow it to scan any detected hard drives.
It should attempt to automatically repair any disk errors.
Please make note of what it does and let me know.
When complete, type
menu then hit Enter.
Type
6 to select Quit then hit Enter.
Press Ctrl+Alt+Del to restart the machine and see if it will boot normally.