Similar problem here. I try to boot to the live environment. The menu starts up ok, and then kubuntu logo and loading progress bar show fine. At the point where I assume the x server starts, I geta green bar on the screen and the PC locks up. This happens in normal and safe graphics. I have tried disabling power management in the boot options.
Hardware: MSI K8N Neo-F (nForce 4) A64 3000+ Ati Radeon X850XTPE -- Install 6:10 Failure: Black screen at Live Desktop Stage https://launchpad.net/bugs/67487 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs