;vm rescue
 

my os partition is lvm partition.i cant access os,while entering only a blink ie boot loader is missing.i have entered rescue mode,still cant access,i want command also step to access it.
if it is linux partition grub-install /dev/sda.

but lvm

Please update your Linux distribution details in your user control panel (http://www.linuxquestions.org/questions/usercp.php).
If you have a installation CDROM or DVD for your distribution at hand try using that in rescue mode.
Also it could help if you told us what you did exactly before it became unbootable.