In my previous post "Computer Hardware Troubleshooting Checklist and How to Fix Them" I wrote about hardware problems that conflict Windows start-up. Read my previous post before this. Now I will tell about some errors within windows causing failure and of course how to fix them. The Windows may not start-up due to the errors in boot configuration. This can be understood if it shows some error before starting up or you get a blank screen. What you have to do is to repair BCD. It is the file that contain Boot Configuration Data in versions of Windows Vista and later. You will need the Windows DVD to do this. Insert the DVD while turning on your system. Then press F12 key on the keyboard while booting and select CD drive (the name of CD drive will be shown) to boot from the DVD. Press any key to continue. Then click on repair your computer. Then click on start-up repair. Select the correct version if you have multiple versions of Windows installed (Leave it if you don't have).The start-up repair would repair the most problems. If the Start-up Repair doesn't recognize the problem, you can use the command prompt. Type "bootrec/fixmbr" and "bootrec/rebuildbcd" and "bootrec/fixboot". Now you can close command prompt and restart your computer. Remove the DVD to prevent it from booting. I hope now everything is perfect.
Sometimes after windows has started up there is a blank screen. Note that this is after we see the Windows welcome screen. Now you could try logging off by pressing Ctrl+Alt+Del and logging in again. If it does not do anything, restart and press F12 continuously before Windows is starting. Now select Last known good configuration and the computer will restart.
If you have dual boot (that is you have other operating systems like Ubuntu alongside Windows) you must have Grub boot loader instead of the Windows boot loader. Sometimes the Grub may get corrupted. If this happens you can install grub from the Installation DVD of Ubuntu. Find more on my other post about installing GRUB. So if you format the partition which Grub is installed from Windows, you will get a grub error instead of Windows starting up. Either you can install grub or Windows boot loader through the method I said above.
Getting an error saying that "Some memory device is not working properly, reconnect and restart"? You are going to need to re-install Windows to repair this. If you get an error while installing Windows that "Failed to update boot configurations", read: How to Fix Error Updating Boot Configuration in Windows.
Suggestions or for any help on doubts, you can leave a comment.