新手求救：开机后进入不了ubuntu8.04

开机后过了ubuntu滚动条的界面后，进入不了桌面。屏幕显示：
BusyBox v1.1.3(debian 1:1.1.3-5ubuntu12)Built-in shell cash)Enter 'help' for a
list built -in commands.
输入了 help 后，屏幕显示：
.:alias break cd chdir command contine echo eval exec exit export false getopts
hash help let local pwd read readonly return set shift times trap ture type ulimit
umask unalias unset wait [[[ash awk hasename busybox cat chmod chroot chrt clear cmp
cp cut deallocvt dumpkmap echo egrep env expr false fbset fdflush fgrep grep hostname
ifconfig ip kill ln loadfont loadkmap is mkdir mkfifo mknod mkswap mktemp more mount
mv openrt pidof printf ps pwd readlink resset rm rmdir set setkeycodes sh sleep sort
stat sync tail tee test touch tr true tty umount uname uniq wget yes
请问怎样才能修复系统？恳请高手们指点一下。