Hello, so I was fixing a friends pc because on boot it would BSOD. I found that the BSOD error was that the necessary boot files were missing. So i booted his drive into Parted Magic and tried to use file manager to recover his files. I could not the drive was unable to mount and had this error:
 
undevil: error 64: unable to determine device fstype - specify with -t
 
So this is when it become weird, I plugged in my hardrvie that was completely functional. I was going to use it to transfer over his files to. 
 
Now my harddrive is messed up just like his, i did a disk health scan had like 200 something errors just like his.  So any harddrive I attached to his computer messed up everything. I cannot access my files on my drive it wont boot or anything. I can re-format them but I want whats on them.
 
Also if I plug my hardrive into my computer it does not let my windows start up which is installed on a completely different drive. It makes no sense. If I unplug it then windows begins to start up. Then I plugged it in at login then my computer would just stay at the login screen loading desktop. 
 
It would be great if anyone could let me know what this is and how to fix it, or an OS that I can boot up on the computer so I can recover my files. My best guess would be a virus that corrupts any drive attached to that computer. I don't have a clue but it just does not make sense to me!

EVGATech_JoseR
Speedrookie, have you tried simply using a completely empty drive and doing a simple OS install without any other HDDs plugged into the board? I imagine during your attempt to transfer the files over from the first drive on to your drive, any corrupted or infected files may have damaged your Windows installation. Typically, a bad SATA controller will not register any drive plugged into it in BIOS and may also put out BSODs which could lead to file corruption. 

I never actually transferred the files I was going to but it then corrupted that drive. Just plugging it in screwed up my drive.

I would run a live boot CD or USB of linux, mount the drives, and see if you can read them from there. 

My reply is a bit late, but just in case it can help:
 
Make sure the UEFI didn't change what disk it is trying to boot to. I've had systems where installing an OS disk would automatically cause the UEFI to change which OS & disk it booted from. (even if it was no longer a valid boot drive)
 
You can use the Windows install media to boot to the recovery environment and from there use Bootrec to repair it. Put your drive back in your own system then follow these steps to get to the command prompt http://support.microsoft.com/kb/927392 and once there, you can use these three commands to repair most fixable Windows boot problems. Start with fixmbr and fixboot, and if those don't work then try rebuildbcd last. Make sure no other HDDs with OS's are plugged into your system. Also, doing this can remove any dual-boot configuration that was previously installed.
 
If it works for your own HDD then you can also use the trick to repair his HDD using your own computer. Windows can boot on almost any motherboard as long as both are AHCI, so you can attempt to fix his drive the same way.