looks like your windows is corrupted but its fixable without losing data.
if your PC loads to the windows loading logo, try spamming shift+f10 until a command console pops up.
type the following :
* chkdsk /f c:
* bootrec /fixmbr
* bootrec /fixboot
* bootrec /rebuildbcd
then restart.
if you cant, you will need to get a Windows installer to help you repair it. you can go to the site below and follow instructions there. prepare a usb drive (at least 8GB) or write into a DVD with the ISO file.
https://www.microsoft.com/en-in/software-download/windows10
once you have it. boot your pc. press F8. and select the usb/dvd to load from. select Repair. troubleshoot. command prompt.
* type "sfc /scannow". restart.
* if not fixed. try startup repair.
* if still not fixed. try system restore.
if it still fails. you will have to do a fresh install of windows. remove your hard disk. attach your HDD to a SATA cable of another computer or a SATA to USB adapter. and copy your files there. reattach your HDD back to your computer. boot from your windows installer. and do a fresh install of windows. delete all partitions. format. install.