the F8 button doesnt work for win10. only for win7/8. thats the reason i asked.
the shift+F10 should normally work when you see the windows logo loading.
you can also check your BIOS first. go to your BOOT menu. disable Secure boot. enable CSM. save & reset. try to check if it boots your windows properly. try the shift+f10 again as well.
if that doesnt work then there is no choice but to do the following below :
you will need to get a Win10 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 (or F2/DEL to BIOS and go to boot menu). 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. if you want to backup your data first, 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.