Lately ... my Windows 10 suddenly having so many problems ... I can't access the Play store even Cortana isn't working ... Please Help Me How To Fix This
Sounds like your Windows install is corrupt. You can try running one or more of the following commands to attempt a repair from an elevated command prompt
chkdsk /f /r t then press Y to run it at the next reboot and reboot
DISM /Online /Cleanup-Image /RestoreHealth
If neither of those resolves the issue you can do a re-install over the existing install, you will just need to download the ISO and create a bootable media If that doesn't work, then you are looking at a clean install which will wipe out everything, so if you have data be sure to back it up.