redhat server down

Hi Guys, came in and found server not booting. it says "An error occured during the file system check. Dropping you to shell"

when i do fsck it says The superblock could not be read or does not describe a correct ext2 filesystem.....

i also did e2fsck -b 8193 /dev/sda, it says the device or resouce busy while trying to open

Any help will be highly appreciated