My computer does not start up

Do you have other accounts on the computer? Do they work? Your windows installation is likely corrupted, and windows may need to be reinstalled. Before you reinstall, try booting in safe mode, and see if it works. Then try running the disk check by opening cmd as administrator, and typing chkdsk C: /r, after that finishes, run sfc by typing sfc /scannow, and DISM by typing dism /online /cleanup-image /restorehealth into the terminal. If it still doesn't work, you can try creating another account in safe mode, or copying your data to a hard drive, and reinstalling windows.