windows defender & security center services keep turning off

Evilan said:

I have not install any other AV. Anyway it seems that the Photo app from microsoft also stopped working: it opens and closes within 0,1 milliseconds when I try to open a image file.

Guess I have no choice but to do a clean install.

I would suggest at this point to do a clean install if this problem is now bleeding over to your other apps.

You could make one final try at running SFC 3X & see if that fixes it if you want to try to avoid a clean install.

Not that it helps now, but down the road consider making a system image. Put it on a external HD/FD that is not connected to your OS all the time to keep it safe from corruption. Make images on a regular basis & this way if the worst should happen, you can revert the entire system back to how it was at the time you made the image file.

System Image - Create in Windows 10 - Windows 10 Forums

A system image is an exact copy of a drive or partition which can be used to restore your PC to the state it was in at the time the image was made. By default, a system image only includes the drives that Windows requires to run, including Windows 10 itself, your system settings, programs, and files. You may also include any other drive in the image if you wish. When you restore your computer from a system image it is a complete restoration, you cannot choose individual items to restore and all of your current programs, system settings, and files are replaced with the contents of the system image.

Evilan said:

I will do that. It's about time I would do a clean install anyway since it's been updated from windows xp to vista, 7 and now 10 through the many years.

Yeah, I think after going through all those updates, starting out with a fresh OS would be the best thing. If you need any help setting up Win 10, there's lots of good tutorials here addressing various issues & fix its.

Windows 10 Tutorials