Unmountable_Boot_Volume?

Working on a friends machine for him.
No defenses, so I installed a few and ran MBAM.
On completion of the scan, the machine locked up. Mouse would not move, keyboard inoperable.
Alternative was a hard restart.
Upon attempting a restart, I get "Unmountable_Boot_Volume.
Code at the bottom is:
0x000000ED (0x82FEB900,0xC0000032,0x00000000,0x00000000)

Machine is Dell Dimension 8200 with Windows XP Home with SP1.
Have removed and reconnected cables and RAM. No help.

 

Been there, tried that.
Will not even boot into Safe Mode anymore.
Cannot even access the Setup to boot from CD.

 

Have no machine capable of slaving the drive internally, but may be able to install inside a USB external case.
As per post 1, have already ensured cable connections.

 

Non-destructive reinstallation to the rescue.

 

Managed to get Windows to boot, but afraid the drive is failing.
Hard drive and CD drive are very slow.
Hard drive is loud and mostly clicking.
CD doesn't even spin except in spurts and sputters.
Sad that I can't even get SP2 installed.
Can't even save his data to USB external drive. Tried to install security programs from a thumbdrive.
Wasn't even seen by the machine.

 

What I thought upon first hearing it.
Must be a first edition of XP to not even have any Service Packs installed.