When important system files break, hardly anything on your machine remains working. Many programs won't be able to start and you will be flooded with error notifications and Bluescreens of Death. Windows 7 has a function to solve that kind
Log In As Root in Live Mode (Linux Mint)
After crashing your system and getting entertaining colored screens on boot, you may have to consider booting in live mode from a bootable device such as an installation DVD or a USB-device. However you'll need to be able to log