Unmountable boot volume blue screen, what should I do?

I was trying to install an update from NVIDIA for my GTX 560, but while it was installing, my computer shut off. After a few minutes, I turned it back on. It got to the Windows boot screen and then had a blue screen error and if left on it would just keep doing that.

A few details about my PC: I haven't added any new hardware or software, I'm running Windows XP Professional 32 bit and Windows XP Professional 64 bit on the same hard drive for about 2 years now. I have 2 other hard drives also, but I don't have one large enough to hold everything from my main hard drive, so formatting isn't an option.

Now, as for what I've done so far: I've scanned the RAM with "memtest - 86 v3.4" and it said that it was good. I scanned the hard drive in question with chkdsk /r and it gets to 50% and tells me something along the lines of "the drive has one or more unrepairable problems". I also tried to use chkdsk on the drive I installed the new copy of Windows XP on and it got to 75% then jumped back down to 50% and stayed there (I had to reboot the pc).

So, after that, I turned off auto reboot and got to read the blue screen error code and I looked it up only to find that nobody seems to have this problem, just problems close to it. The error code is 0x000000ed and I've seen a lot of these online but none that matched the detailed part of the code

UNMOUNTABLE_BOOT_VOLUME 0x000000ed (0xfffffadf513c19a0, 0xffffffffc0000006, 0, 0)

So, I have installed another copy of Windows XP Professional 32 bit on one of my other hard drives in hopes of accessing the data on the drive in question and when it booted it asked if I wanted chkdsk to scan the drive in question and this is what it found: file record segments 12740, 12741, 12742 and 12743 were reported unreadable. Then it says "recovering lost files" but it sits there for a few seconds and then just boots to Windows. I can't access the drive in question from Windows as far as I can tell, it just says "drive not accessible" and when I go to properties it says that the drive has 100% free space. So, after that failed I didn't give up, I looked for another way to access the drive in question. I used a Ubuntu bootable disk and was able to access the drive in question without any problems.

However, I can't access the registry editor because it's a .exe file and that won't load from Ubuntu. I made a copy of the "Windows" folder and put it on one of my other drives and that's where I'm stuck at now. I'm sure my drive works fine, I know chkdsk can't fix the problem with it and I know what caused the problem in the first place for the most part, but I don't know what to do about it. I have a laptop that I can use to download and burn disks if needed and I also have the other copy of Windows XP Professional 32 bit that I can use that's installed on the computer in question (so I know it's not a hardware issue). I'm pretty sure it's a driver issue or the update was editing the registry when it shut off and left me when a broken registry.

I've tried accessing C:\Windows\System32\CONFIG only to find that the Windows XP disk repair option can't even access the files on the drive in question. It seems I'll need to be able to do everything from Ubuntu unless there is something I haven't tried with the Windows XP disk. I didn't install the update on Windows XP 64 bit but yet it also has the same blue screen error (that's where the error code above came from but I haven't checked to see if they are the same). They both stopped working at the same time, so I assume it's one problem causing both to not work.

While I appreciate a lot of detail, I think your question can be summarised as follows:

My computer spontaneously shut off while I was installing software. When I turned it back on it got to the Windows boot screen followed by a blue screen of death. ( unmountable_boot_volume ).

Scandisk from a working windows installation hangs on this drive, but a Ubuntu bootable disk is able to access the drive in question without any problems.

I have multiple drives in this computer, but not enough space to back up everything.

This all seems to indicate a problem with a filesystem on the drive in question. (Not with the drive hardware itself, because then Ubuntu would not be able to read it.)

The obvious solution would be to start with a new filesystem (read format it). Which means you need to store your data somewhere. Since you can read it with Ubuntu this should not be a problem. Just use your normal backup drive.

• If you have a backup drive, use that.
• If you have enough space on the other drive, move it there.
• If you can borrow a portable drive from a friend, do that.

Copy all data, boot from a windows CD and reformat the drive. If possible split the drive in two or three partitions. (One partition per OS, on for the data). Format the partitions (it now has a clean working filesystem) and install XP. Copy the data back and return the borrowed drive to your friend.