After abnormal booting the server, I find that I cannot use other user to log in the system. I log in with root user, I su other user, it prompt 'no such directory or file', I find these messages in dmesg.
ext3_orphan_cleanup: deleting unreferenced inode 704664
ext3_orphan_cleanup: deleting unreferenced inode 509426
ext3_orphan_cleanup: deleting unreferenced inode 509425
ext3_orphan_cleanup: deleting unreferenced inode 509423
ext3_orphan_cleanup: deleting unreferenced inode 509422
ext3_orphan_cleanup: deleting unreferenced inode 509421
ext3_orphan_cleanup: deleting unreferenced inode 4685859
ext3_orphan_cleanup: deleting unreferenced inode 4705863
ext3_orphan_cleanup: deleting unreferenced inode 4703920
ext3_orphan_cleanup: deleting unreferenced inode 4705859
ext3_orphan_cleanup: deleting unreferenced inode 4705877
ext3_orphan_cleanup: deleting unreferenced inode 1163331
ext3_orphan_cleanup: deleting unreferenced inode 4704406
ext3_orphan_cleanup: deleting unreferenced inode 4704405
Can anyone help me to explain what is wrong with this server or how to check it?

sounds like /home is a dedicated partition, so unmount it, dropping down to runlevel 1 (run "init 1") is probably a good idea, then run "fsck /dev/<whatever home is>" and see how it gets on recovering the filesystem.