So as expected, Kubuntu 12.10 Live Boot didnt boot up. I had to disable all options-F6-noapm, noapic, nolapic etc, to get it to boot.
Once booted, I reused my /home partition, and wiped / and /boot from my Debian system.
Once installed, on first boot, it showed me a broken graphic and hung up. Ctrl-F1 to open the terminal didnt work either.
So download the latest NVIDIA Ubuntu package (it ends in .run)
Boot to the Ubuntu recovery environ-Grub2>Ubuntu Advanced>Recovery
Choose the menu option to drop to shell
Check if root and home file systems are mounted. If not mount them.
Run an fdisk -l and see file systems
on Trying a mount command, it told me that fstab is probably incorrect.
So see the mount with cat /proc/mounts
I found that / was read only so remounted as rw
mount -o remount,rw /
Now I can run the NVidia package.
Edit: Still didnt boot with kernel.
Finally, booted to recovery, installed the following linux kernel headers:
apt-get install linux-headers-generic linux-headers
Now, install the proprietary Nvidia drivers:
K Menu>Applications>System>Additional drivers
Choose any of the proprietary drivers