christopher heiser <christopher AT heiser DOT net>
Date Published: August 31st, 2009
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Fix a Broken or Missing Bootloader in Windows 7

So like many out there I've been trying out the Windows 7 beta on my PC. Short review: better than XP and not a pile of garbage like Vista. Things actually run faster than XP which impressively bucks the trend for Microsoft product evolution.

I decided to keep XP on the same machine and install Windows 7 onto a new hard drive. This is accomplished very easily: Win7 replaces the old XP bootloader (which lives on the old XP drive) and allows you to select either XP or Win7 at startup. Nice!

Unfortunately for me, my XP drive is actually a Raid 0 array with Raptor drives. I'd already had one fail, and yesterday the other failed as well. With Raid 0, there is no recovery, the drive is just gone and with it, the bootloader--meaning that the machine would not boot.

It turned out to be a little more complicated than I thought to get things running again. Here is the step-by-step process of creating a new bootloader on the disk that has the Win7 install:

  1. Reconfigure your BIOS to boot from the DVD first and then the Win7 drive
  2. Boot the machine from the Win7 DVD
  3. After the language select screen, choose "Repair your computer" from the lower left
  4. The system will not find any installations. This is okay, click the top radio button and hit Next
  5. You'll see a list of "System Recovery Options". Open up the Command Prompt
  6. Try typing the following commands in order: "bootrec /fixmbr", "bootrec /fixboot", "bootrec /rebuildbcd". If these complete successfully, go ahead and skip the next step. However, if any of these steps reports "Element cannot be found" you need to reconfigure the disk configuration.
  7. You're going to use DISKPART to make the Win7 partition active. You can type "HELP" for a list of commands or check out Microsoft's help page. Basically you select the drive first ("LIST DRIVES" and then "SELECT DRIVE [number]") and then the partition ("LIST PARTITION" and then "SELECT PARTITION [number]") where Win7 is installed. Then type "ACTIVE" to make the selected partition active. Once this is finished, repeat the previous step.
  8. With the bootloader now created, we need to let Win7 configure it. Restart and boot from the DVD again, and choose the same repair option as before. Now you should see your Win7 installation listed. Allow the installer to repair the system. You may have to repeat this step once or twice, but eventually the bootloader will be fixed and your machine will work again!

You may get better mileage out of this alternative way of creating a new bootloader which I found after I had already gotten things working again.

I suspect this is going to be a very common problem for people who are dual booting to multiple disks and removing or reformatting their old XP/Vista drive once they have made a clean break to Win7.

by Christopher Heiser on August 31 16:13
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