[all variants] Lucid reboots at login or imediatly after login

view full story

http://ubuntuforums.org – This problem always happend to me, i tried the ubuntu alpha3 and now the kubuntu version. iI have a kubuntu alpha 3 cd, booted from it and at login the laptop rebooted. I tried again, Press F6 at grub menu and chose acpi=off noapic and nomodeset. After this i booted and installed kubuntu successfully. I started in safe mode and made all the updates, now after reboot i get that reboot at login or if i try to login in fluxbox after a few seconds after fluxbox loads. I tried using acpi=off noapic and nomodeset, i tried xforcevesa and even creating a xorg.conf and set vesa insted of radeon. (Hardware)