Recently I suffered from a total system breakdown. Windows suddenly decided to stop booting, I didn't believe the cause of the error was bad hardware (faulty HDD) - the laptop is new.
I struggeled to find a solution, tried many things with the Windows installation disks. None of the automatic repair tools helped (system restore, automatic startup repair, boot-repair-disk).
It seemed the cause of the error was a broken MBR, caused by a process with access to system files, but boot-repair-disk didn't fix it.
After some more googling I found out that the Windows installation disk has another MBR fix tool, accessable from the command prompt.
Boot the system from the Windows installation DVD, then open up command prompt either with Shift+10 or by choosing it from the menu.
Then type:
bootsect.exe /nt60 C:
