First post indicates that priority was moving files from partition...second post, you want to boot the system.
FWIW: The typical solution for the Unmountable Boot Volume error...is to run the chkdsk /r command on the partition in question.http://support.microsoft.com/kb/555302
IMO, when chkdsk /r runs into problems that it cannot handle, it's usually one of two things:
a. The NTFS file system is awry or there is some problem with the partition tables. My experience is that chkdsk /r will spell out the problem if it's either of these.
b. The hard drive itself has problems.
If the hard drive itself has problems...the important thing is to move valued files from it...before anything else.
After such files have been moved, then it's time to try to better define the problem with the partition/drive. That calls for a hard drive diagnostic utility.
Hard Drive Installation and Diagnostic Tools - http://www.bleepingcomputer.com/forums/t/28744/hard-drive-installation-and-diagnostic-tools/