Stop 0x000000ED or UNMOUNTABLE_BOOT_VOLUME

Causes: The kernel mode I/O subsystem attempted to mount the boot volume and it failed.

File system structural corruption.
Upgrade to Windows XP Professional on systems that use higher throughput ATA disks or controllers with incorrect cabling.
Higher transfer rates when using the incorrect cable type.
 

Solutions:

       • Run any system diagnostics that are supplied by your computer manufacturer, especially a HDD check.
       • Run the CHKDSK /r to repair the File System.
       • If the Hardware is fully functional reinstall the Operating System.