This week, my friend brought her computer to see me. Her computer can load up a Windows starting screen for a few seconds and it got a blue screen with an error message, "Unbootable Boot Volume". That doesn't seem like a hardware failure, because it can load the start up screen. I found a Windows Vista Setup DVD. I loaded it up. After the first screen which asks me to choose the language, there is a screen with the option for Recovery Console. Then I selected it this one. After that, I chose the Command Prompt. Then I typed "chkdsk C:/r". Then "Waiting.....". After an hour, it scanned the disk and repaired the files damaged. I removed the DVD and rebooted it. It works again!
Reference:
Windows Support