On my Asus N56VZ notebook I have a UEFI multi boot setup with Win7, Ubuntu 12.04 and Mint 13. This configuration has been working fine, so far. However, a few days ago I decided to upgrade Ubuntu using "sudo apt-get upgrade" command.
Now I only get the command line when I boot into Ubuntu. Both Win7 and Mint are still booting fine.
I've read that I'd end up with a cleaner OS, if I choose to reinstall instead of upgrading. Since I am experiencing problems with Ubuntu already, I see no reason for keeping the current install.
I am concerned about the other partitions, so I'd appreciate some guidance on how to safely replace the broken Ubuntu with a clean installation of 13.04.