toshiba portege m100 stopped upgrading from ubuntu 12. to 13.
I have a toshiba portege m100 that I couldn't locate a recovery disk for, so I installed the ubuntu 12.3, and it was working fine. Then, I got a message to upgrade to the 13.04 version, and as it was going thru the process, it stopped and I got a message that it couldn't continue the upgrade. Now, when I log into the the OS, my computer will not boot up to let me go online. What should I do, to reinstall the old 12.3 version? When I tried to reinstall the OS with the disk, it doesn't recognize the disk in the drive. Please help me...thnx much.