OS seems missing after update, how can I retrieve files?

Hey all. I'm attempting to fix the computer of someone I work with. It's an HP Compaq 8000 Elite running Windows 7 Professional.

According to him, 3 updates were recently installed. After the updates completed, the computer rebooted, then the "BOOTMGR is missing" error message came up.

I searched the web for solutions to that particular issue, and the main consensus seems to be to run a repair from the Windows 7 installation disc. I tried that, but when the recovery manager searched for installed operating systems, it found nothing.

I went to the command prompt in the recovery manager and typed "C:" to try and determine if anything was installed. The C: drive was labeled "OS", but there didn't appear to be anything on it other than a TEMP folder.

Then I ran Ubuntu via flash drive, which allowed me to access the corrupt hard drive. However, I only saw that TEMP folder, which contained text documents.

Now I have the corrupt hard drive plugged into my personal desktop, as a final attempt at retrieving any files. When I navigate to My Computer to see the connected drives, I now see:

Local Disk (C:) - My main hard drive

OS (E:) - What I assume would be the OS partition of my co-worker's drive, but it says 39.9 GB free of 39.9 GB (It's supposed to be a 500 GB drive).

SYSTEM (F:) - 1.95 GB free of 1.99 GB. Not too sure what this one is.

HP_RECOVERY (G:) - I know this is the partition of his drive dedicated to restoring the OS to factory settings.

I would love to return the computer in working order with it's original files, but it looks like the OS is just completely corrupt. The next best thing would be to save his files to an external HDD and wipe the drive, but I can't even access those.

Anyone here have any suggestions? Things look pretty bleak, so I'm up for trying anything, even any crazy home remedies like pulling the drive and smacking it with a baseball bat :whistling: .

Thanks in advance.