I have some new information. This issue has something to do with processor type. I replaced nothing more but processor to Pentium Dual E2160 and suddenly x64 live cd managed to boot sucessfully. I took lspci, lshw and dmidecode of this 'upgraded' system, see attachment 'acpi-e2160.zip'.
Symmetrically, when I installed 'Intel(R) Core(TM)2 CPU 6600' into other computer (namely Optiplex 755) it stopped to boot on x64 bit version. So processor type seems to be the clue. ** Attachment added: "acpi-e2160.zip" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1243431/+attachment/3896118/+files/acpi-e2160.zip -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1243431 Title: Ubuntu 13.10 64bit installer won't boot unless acpi=off on Dell Optiplex 745 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1243431/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
