Yesterday while upgrading from 11.4 to 11.10, due to power cut my system crashed.

Ubuntu is unable to boot. While booting I get two options in grub, one is for recovery mode and the other is for normal ubuntu booting (and others are also thr for mem check and booting to windows). When I try to boot it normally, it pauses booting while displaying ' Checking battery statues' . Though i am not using a laptop, I am on a desktop.

And In recovery mode the menu has 4 options - resume boot, fsck , remount and root ( to goto shell prompt) . If I go to shell and type ' apt-get dist upgrade' , it shows -

W: not using locking for read only lock file /var/lib/dpkg/lock
E:unable to write to /var/cache/apt
E:The package lists or status files could not be parsed or opened.

Please instruct me to recover from this situation.