Same Problem here. I moved Kubuntu 12.04 from old PC to this new PC, runs without problem but needed to upgrade to 12.10 because of a softwareproblem. 12.10 also runs without problems. Because upgrade to 13.10 did not work I installed 14.04 new from USB, install reboots every few seconds, no matter if I press any button, try to install or just wait, a few seconds after boot it reboots.
Adding radeon.dpm=0 to boot options solved installer. After install kubuntu reboots again after a few seconds. Adding radeon.dpm=0 to grub- boot-line starts ok. Now added radeon.dpm=0 to grub-conf Hardware: MSI A78M-E35 (MS-7721) and AMD A4-4020 APU with Radeon(tm) HD Graphics Also addes dmesg.1.gz from first boot without radeon.dpm=0 Hope this helps somehow, have PC only till tomorrow, it's from my neighbour ** Attachment added: "dmesg.1.gz" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1309578/+attachment/4095441/+files/dmesg.1.gz -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1309578 Title: Ubuntu 14.04 suddenly reboots when booting from Live USB (AMD APU's) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1309578/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs