Startup Repair tries to diagnose and fix some common boot problems automatically. It is the easiest and the safest of the built-in Windows recovery options. It is usually considered the first resort in solving boot problems.
Startup Repair is not something you usually need to start manually. Windows sets a status flag at the time of startup to indicate that the boot process has started, this flag is cleared after a successful boot. If the boot fails, the flag is not cleared. The next time you start the computer Windows will see the flag and should start the Windows Recovery Environment and run Startup Repair automatically.
The automatic switch to Windows RE depends on the boot manager and the Recovery Partition. Certain types of failures can prevent Windows RE from starting. In this the case you need to use a Recovery disk or a Windows installation disk to run Startup Repair.
You have to consult your motherboard’s documentation to find out how to boot from a USB or CD. You need to press some magic key while the system is booting up. The key is dependent on the manufacturer.
If you are booting using a Windows installation disk, choose the Repair Your Computer option. This will take you to the Boot Options Menu which contains the various boot related options like Startup Repair
If you are booting from a recovery disk you will be booting straight to the Boot Options Menu.
From the Boot Options Menu, choose Troubleshoot.
From the Troubleshoot screen, choose Advanced Options.
In the Advanced Options screen choose Startup Repair.
Choose your Windows account.
Enter the password and click Continue. If you have not set up a password for your account, leave the password box blank and click Continue.
Windows would now try to diagnose and repair startup problems. As mentioned before the process is automatic and no manual interaction is needed during the repair process. If the repair is successful the computer would automatically restart. If it fails then you will see a message saying startup repair could not repair your PC.
If startup repair fails, it would show you a path to a log file which contains a record of the problems that it found, as well as the steps it tried to repair the PC. The contents of the log file might assist you in troubleshooting further. In order to view the log and perform troubleshooting based on it, you need to access the command prompt which you can find in the advanced troubleshooting screen.
If recovering using the command line is not possible, then you may have to look at more destructive options. The options left are System Restore, System Image Recovery and finally the Reset the PC option. System restore should probably be your next choice. It is the same as the Last Known Good Configuration option from previous versions of Windows. It resets what Windows considers to be system changes, but leaves your personal files intact. System Image Recovery can recover the PC using a system image, in case you have created one in advance. This technique is more reliable than System Restore, but you will lose all the modifications you made after creating the image, including your personal files. Reset the PC is like a factory reset, it removes all your apps and settings but gives you the option to keep your personal files.